A CREATE...SELECT that fails is written to the binary log if a non-transactional
statement is updated. If the logging format is ROW, the CREATE statement and the
changes are written to the binary log as distinct events and by consequence the
created table is not rolled back in the slave.

In this patch, we opted to let the slave goes out of sync by not writting to the
binary log the CREATE statement. We do this by simply reseting the binary log's
cache.

mysql-test/suite/rpl/r/rpl_drop.result:
  Added a test case.
mysql-test/suite/rpl/t/rpl_drop.test:
  Added a test case.
sql/log.cc:
  Introduced a function to clean up the cache.
sql/log.h:
  Introduced a function to clean up the cache.
sql/sql_insert.cc:
  Cleaned up the binary log cache if a CREATE...SELECT fails.