to the data dictionary records.  This should fix Issue #83.

row_drop_table_for_mysql_no_commit(): Rename back to
row_drop_table_for_mysql().  Commit the transaction if the data
dictionary was not locked when the function was called.  Otherwise,
neither commit the transaction nor unlock the data dictionary.

row_merge_drop_table(): Let row_drop_table_for_mysql() take care of
locking the data dictionary.

dict_create_or_check_foreign_constraint_tables(),
trx_rollback_active(), row_create_table_for_mysql(),
row_create_index_for_mysql(), row_table_add_foreign_constraints():
Explicitly commit the transaction, because row_drop_table_for_mysql()
would no longer commit it, given that the data dictionary will be
locked during the calls.

Approved by Sunny (over IM). rb://23