Note: Backporting the patch from mysql-5.6.

Problem:

A CREATE TABLE with an invalid table name is detected
at SQL layer. So the table name is reset to an empty
string.  But the storage engine is called with this
empty table name.  The table name is specified as
"database/table".  So, in the given scenario we get
only "database/".

Solution:

Within InnoDB, detect this error and report it to
higher layer.

rb#9274 approved by jimmy.