PMFS: Fix broken error condition in pmfs_rename

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Vishal Verma <vishal.l.verma@linux.intel.com>
PMFS: Flush shared variable while holding lock

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Vishal Verma <vishal.l.verma@linux.intel.com>