data directory name command

The check_db_name function has been modified to validate tails of
#mysql50#-prefixed database names for compliance with MySQL 5.0
database name encoding rules (the check_table_name function call
has been reused).


mysql-test/r/renamedb.result:
  Updated test case.
mysql-test/r/upgrade.result:
  Test case for bug #53804.
mysql-test/t/renamedb.test:
  Updated test case.
mysql-test/t/upgrade.test:
  Test case for bug #53804.
sql/mysql_priv.h:
  Bug #53804: serious flaws in the alter database .. upgrade
              data directory name command
  
  The check_mysql50_prefix has been added.
sql/sql_table.cc:
  Bug #53804: serious flaws in the alter database .. upgrade
              data directory name command
  
  - The check_mysql50_prefix has been added.
  - The check_n_cut_mysql50_prefix function has been refactored
  to share code with new check_mysql50_prefix function.
sql/table.cc:
  Bug #53804: serious flaws in the alter database .. upgrade
              data directory name command
  
  The check_db_name function has been modified to validate tails of
  #mysql50#-prefixed database names for compliance with MySQL 5.0
  database name encoding rules.

  UPGRADE)

Bug 17565 (RENAME DATABASE destroys events)
Bug#28360 (RENAME DATABASE destroys routines)

Removed the
  RENAME DATABASE db1 TO db2
statement.

Implemented the
  ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
statement, which has the same function.


client/mysqlcheck.c:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/r/create.result:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/r/query_cache.result:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/r/renamedb.result:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/r/sp-code.result:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/r/sp-error.result:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/r/upgrade.result:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/t/create.test:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/t/query_cache.test:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/t/renamedb.test:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/t/sp-error.test:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
mysql-test/t/upgrade.test:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
sql/mysql_priv.h:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
sql/sql_lex.h:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
sql/sql_parse.cc:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
sql/sql_prepare.cc:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
sql/sql_yacc.yy:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME
sql/sql_db.cc:
    ALTER DATABASE db UPGRADE DATA DIRECTORY NAME

Problem:
Renaming a database to itself crashed server.
It hapenned because of wrong DBUG_ASSERT.
Fix: removing wrong DBUG_ASSERT. Now it reports
a correct error message "database alreadt exists".


mysql-test/r/renamedb.result:
  Adding test case
mysql-test/t/renamedb.test:
  Adding test case
sql/sql_db.cc:
  DBUG_ASSERT crashed server when renaming a database to itself.

  new file
Many files:
  WL#757 RENAME DATABASE


sql/mysql_priv.h:
  WL#757 RENAME DATABASE
sql/mysqld.cc:
  WL#757 RENAME DATABASE
sql/sql_db.cc:
  WL#757 RENAME DATABASE
sql/sql_lex.h:
  WL#757 RENAME DATABASE
sql/sql_parse.cc:
  WL#757 RENAME DATABASE
sql/sql_rename.cc:
  WL#757 RENAME DATABASE
sql/sql_table.cc:
  WL#757 RENAME DATABASE
sql/sql_yacc.yy:
  WL#757 RENAME DATABASE