port from mysql-next (5.4?) to mysql-next-mr-bugfixes (5.5/5.6?)

3477 Mikael Ronstrom	2009-07-29
Bug#32115, made use of local lex object to avoid side effects of opening partitioned
tables

3478 Mikael Ronstrom	2009-07-29
Bug#32115, added an extra test in debug builds to ensure no dangling pointers to the
old lex object is still around

3479 Mikael Ronstrom	2009-07-29
Bug#32115, Removed an assert that was no longer needed

3480 Mikael Ronstrom	2009-08-05
Bug#32115, fixed review comments

3481 Mikael Ronstrom	2009-08-07
Bug#32115, remove now obsolete lex_start calls