locks on the table

Fixing the partitioning specifics after TRUNCATE TABLE in
bug-42643 was fixed.

Reorganize of code to decrease the size of the giant switch
in mysql_execute_command, and to prepare for future parser
reengineering. Moved code into Sql_statement objects.

Updated patch according to davi's review comments.

libmysqld/CMakeLists.txt:
  Added new files.
libmysqld/Makefile.am:
  Added new files.
mysql-test/r/not_partition.result:
  now returning error on partitioning commands
  if partitioning is not enabled.
mysql-test/r/partition_disabled.result:
  There is no partition handlerton, so it cannot
  find the specified engine in the .frm file.
mysql-test/r/partition_truncate.result:
  Updated test results.
mysql-test/suite/parts/inc/partition_mgm.inc:
  Added check that TRUNCATE PARTITION does not delete on failure.
mysql-test/suite/parts/r/partition_debug_sync_innodb.result:
  updated results.
mysql-test/suite/parts/r/partition_mgm_lc0_archive.result:
  updated results.
mysql-test/suite/parts/r/partition_mgm_lc1_archive.result:
  updated results.
mysql-test/suite/parts/r/partition_mgm_lc2_archive.result:
  updated results.
mysql-test/suite/parts/t/partition_debug_sync_innodb.test:
  Test case for this bug.
mysql-test/t/not_partition.test:
  Added check for TRUNCATE PARTITION without partitioning.
mysql-test/t/partition_truncate.test:
  Added test of TRUNCATE PARTITION on non partitioned table.
sql/CMakeLists.txt:
  Added new files.
sql/Makefile.am:
  Added new files.
sql/datadict.cc:
  Moved out the storage engine check into an own
  function, including assert for lock.
sql/datadict.h:
  added dd_frm_storage_engine.
sql/sql_alter_table.cc:
  moved the code for SQLCOM_ALTER_TABLE in mysql_execute_command
  into its own file, and using the Sql_statement object to
  prepare for future parser reengineering.
sql/sql_alter_table.h:
  Created Sql_statement object for ALTER TABLE.
sql/sql_lex.cc:
  resetting m_stmt.
sql/sql_lex.h:
  Temporary hack for forward declaration of enum_alter_table_change_level.
sql/sql_parse.cc:
  Moved out ALTER/ANALYZE/CHECK/OPTIMIZE/REPAIR TABLE
  from the giant switch into their own Sql_statement
  objects.
sql/sql_parse.h:
  Exporting check_merge_table_access.
sql/sql_partition_admin.cc:
  created Sql_statement for
  ALTER TABLE t ANALYZE/CHECK/OPTIMIZE/REPAIR/TRUNCATE
  PARTITION. To be able to reuse the TABLE equivalents.
sql/sql_partition_admin.h:
  Added Sql_statement of partition admin statements.
sql/sql_table.cc:
  Moved table maintenance code into sql_table_maintenance.cc
sql/sql_table.h:
  Moved table maintenance code into sql_table_maintenance.h
  exporting functions used by sql_table_maintenance.
sql/sql_table_maintenance.cc:
  Moved table maintenance code from sql_table.cc
sql/sql_table_maintenance.h:
  Sql_statement objects for ANALYZE/CHECK/OPTIMIZE/REPAIR TABLE.
  Also declaring the keycache functions.
sql/sql_truncate.cc:
  Moved code from SQLCOM_TRUNCATE in mysql_execute_command into
  Truncate_statement::execute.
  Added check for partitioned table on TRUNCATE PARTITION.
  Moved locking fix for partitioned table into
  Alter_table_truncate_partition::execute.
sql/sql_truncate.h:
  Truncate_statement declaration (sub class of Sql_statement).
sql/sql_yacc.yy:
  Using the new Sql_statment objects.