LU-11085 ldlm: change lock_matches() to return bool.

LU-11085 ldlm: change lock_matches() to return bool.

The name of the function lock_matches() sounds like it
performs a test (it does) and so should return a bool.
Returning a bool gives a slight code simplification (in
search_queue) and more simplification in future patches.

Linux-commit: e16983d96c775eb4527208d3c3d13f57e6d6233c

Change-Id: I1e3a09a0768abd0ab1cfada0fd69216cb9e85df7
Signed-off-by: Mr. NeilBrown <neilb@suse.de>
Reviewed-on: https://review.whamcloud.com/33854
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>