When having a sub query in partitioned innodb one could
make the partitioning engine to search for a 'index_next_same'
on a partition that had not been initialized.

Problem was that the subselect function looks at table->status
which was not set in the partitioning handler when it skipped
scanning due to no matching partitions found.

Fixed by setting table->status = STATUS_NOT_FOUND when
there was no partitions to scan. (If there are partitions to
scan, it will be set in the partitions handler.)