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

2755 Konstantin Osipov	2008-11-27
Bug#32115 will remove the pre-requisite to initialize LEX to open tables.
This dependency was added in 5.1 and was supposed to be removed in 6.0.
Remove asserts and initialization of LEX in places where we don't deal
with partitioned tables.