cluster/afr: Disable delayed post op when eager-lock is off

Problem:
When eager-lock is disabled, inodelks for write-fops on same
fd conflict with each other. If eager-lock is disabled but
delayed post-op is enabled then each write fop's inodelk unlock
waits for post-op-delay-secs. So the conflicting write fop
acquires inodelk after post-op-delay-secs. This results in
post-op-delay-secs delay for every write fop on the fd for
sequential writes (Ex: dd).

Fix:
Disable delayed-post-op when eager-lock is off.

Change-Id: I87ea4c8d1c7bb269b9b174388ae50f37e82629b7
BUG: 895235
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/4391
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>