This patch fixes two problems described as follows:

1 - If there is an on-going transaction and a temporary table is created or
dropped, any failed statement that follows the "create" or "drop commands"
triggers a rollback and by consequence the slave will go out sync because
the binary log will have a wrong sequence of events.

To fix the problem, we changed the expression that evaluates when the
cache should be flushed after either the rollback of a statment or
transaction.

2 - When a "CREATE TEMPORARY TABLE SELECT * FROM" was executed the
OPTION_KEEP_LOG was not set into the thd->options. For that reason, if
the transaction had updated only transactional engines and was rolled
back at the end (.e.g due to a deadlock) the changes were not written
to the binary log, including the creation of the temporary table.
      
To fix the problem, we have set the OPTION_KEEP_LOG into the thd->options
when a "CREATE TEMPORARY TABLE SELECT * FROM" is executed.

sql/log.cc:
  Reorganized the code based on the following functions:
  
  - bool ending_trans(const THD* thd, const bool all);
  - bool trans_has_updated_non_trans_table(const THD* thd);
  - bool trans_has_no_stmt_committed(const THD* thd, const bool all);
  - bool stmt_has_updated_non_trans_table(const THD* thd);
sql/log.h:
  Added functions to organize the code in log.cc.
sql/log_event.cc:
  Removed the OPTION_KEEP_LOG since it must be used only when
  creating and dropping temporary tables.
sql/log_event_old.cc:
  Removed the OPTION_KEEP_LOG since it must be used only when
  creating and dropping temporary tables.
sql/sql_parse.cc:
  When a "CREATE TEMPORARY TABLE SELECT * FROM" was executed the
  OPTION_KEEP_LOG was not set into the thd->options.
        
  To fix the problem, we have set the OPTION_KEEP_LOG into the
  thd->options when a "CREATE TEMPORARY TABLE SELECT * FROM"
  is executed.