Added new commands CREATE USER and RENAME USER.
Changed behaviour of DROP USER.
Changed an error messages for the new commands.


Docs/mysqld_error.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
include/mysqld_error.h:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Changed an error code for more general use.
mysql-test/r/grant.result:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Changed test results.
mysql-test/r/grant2.result:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  New test results.
mysql-test/r/ps_1general.result:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Changed test results.
mysql-test/t/grant.test:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Updated old tests for new behaviour of DROP USER.
  It does now implicitly remove all privileges and
  does not fail when privileges are still in place.
  Fixed a typo, which left an user in the database,
  whereby other tests could be confused.
  Added a DROP USER for another test user.
mysql-test/t/grant2.test:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Added new tests for the new features.
sql/share/czech/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/danish/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/dutch/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/english/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/estonian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/french/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/german/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/greek/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/hungarian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/italian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/japanese/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/korean/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/norwegian-ny/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/norwegian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/polish/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/portuguese/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/romanian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/russian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/serbian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/slovak/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/spanish/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/swedish/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/share/ukrainian/errmsg.txt:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Modified an error message for more general use.
sql/sql_acl.cc:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Added a destructor for the GRANT_TABLE object to get
  rid of a hash_column in cases where a nonsense row was
  read from the privilege tables. Added code to delete
  such an object when it is not entered into the 
  column_priv_hash due to a nonsense row.
  Added function comments to two unmodified functions.
  Replaced mysql_drop_user() by the implementation of all
  of the functions as specified in the Low Level Design.
sql/sql_acl.h:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Added prototypes for new functions.
sql/sql_lex.h:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Added new command codes for CREATE USER and
  RENAME USER.
sql/sql_parse.cc:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Added case clauses for the new commands CREATE USER
  and RENAME USER.
sql/sql_yacc.yy:
  WL#2050 - CREATE USER and DROP USER and RENAME USER
  Added syntax for the new commands CREATE USER and 
  RENAME USER, reworked DROP USER, introduced a new
  'user_list' and 'rename_list', renamed the old 
  'user_list' to 'grant_list'. The difference is that
  'grant_list' contains 'grant_user' (with optional
  IDENTIFIED BY), while 'user_list' contains 'user'.
  Concentrated privilege initializazions into a new
  section 'clear_privileges'.