GFS2: Optimize glock multiple-dequeue code

This is a small patch that optimizes multiple glock dequeue
operations.  It changes the unlock order to be more efficient
and makes it easier for lock debugging tools to unravel.  It
also eliminates the need for the temp variable x, although
that would likely be optimized out.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>