cluster/afr: Perform wakeup just before fop

There is no necessity for the delayed-post-op to wait until
the next fop phase on the fd completes. Change-log,
locks are inherited by the time next fop phase is attempted
so the wakeup can happen just before the fop phase is started.

Change-Id: I0b8e591f591b0f7565eb55265ab51f476ed2b165
BUG: 908302
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/4073
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>