WITH REPLICATE-REWRITE-DB FAILS

Problem:
=======
As part of fix for BUG#16290902, at the time of writing the
'DROP TEMPORARY TABLE IF EXISTS' query into the binlog, the
query will not be preceded by a 'use `db`' statement. The
query will have a fully qualified table name.

Eg:
'USE `db`; DROP TEMPORARY TABLE IF EXISTS `t1`;'
will be logged as
'DROP TEMPORARY TABLE IF EXISTS `db`.`t1`;'.

Because of this change application of 'replicate-rewrite-db'
filter rule will fail on slave, as it works only on default
database specified in 'use' statement. This causes slave to
break when the 'CREATE TEMPORARY TABLE' is re-executed on
slave.

Analysis:
========
The intention of BUG#16290902 fix was to address a specific
scenario where the default database does not exist on the
slave but in spite of that DROP TEMPORARY TABLE IF EXITS
query will be binlogged with 'USE default_db' statement.
Which causes point in time recovery to fail when user uses
Slave's binary log to re-apply. But the fix that was more
generic. It completely removed 'USE default_db' for DROP
TEMPORARY TABLE IF EXITS queries even when they have their
default databases present. Hence the scope of the fix should
have been narrowed.


Fix:
===
At the time writing 'DROP TEMPORARY TABLE IF EXISTS' query
into the binary log, check if the default database exists.
If it exists then write 'USE default_db' in the binary log.
If default database is not present then log the query with
qualified table name.