dlm: fix basts for granted CW waiting PR/CW

The fix in commit 36509258 was addressing
the case of a granted PR lock with waiting PR and CW locks.  It's a
special case that requires forcing a CW bast.  However, that forced CW
bast was incorrectly applying to a second condition where the granted
lock was CW.  So, the holder of a CW lock could receive an extraneous CW
bast instead of a PR bast.  This fix narrows the original special case to
what was intended.

Signed-off-by: David Teigland <teigland@redhat.com>