gfs2: glock cancelation flag fix

gfs2: glock cancelation flag fix

When an asynchronous glock holder is dequeued that hasn't been granted
yet (HIF_HOLDER not set) and no dlm operation is in progress on behalf
of that holder (GLF_LOCK not set), the dequeuing takes place in
__gfs2_glock_dq().  There, we are not clearing the HIF_WAIT flag and
waking up waiters.  Fix that.

This bug prevents the same holder from being enqueued later (gfs2_glock_nq())
without first reinitializing it (gfs2_holder_reinit()).  The code
doesn't currently use this pattern, but this will change in the next
commit.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>