cluster/afr: Turn on eager-lock for fd DATA transactions

Problem:
With the present implementation, eager-lock is issued for
any fd fop. eager-lock is being transferred to metadata
transactions. But the lk-owner is set to local->fd address
only for DATA transactions, but for METADATA transactions
it is frame->root. Because of this unlock on the eager-lock fails
and rebalance hangs.

Fix:
Enable eager-lock for fd DATA transactions

This is a backport of change If30df7486a0b2f5e4150d3259d1261f81473ce8a
http://review.gluster.org/#/c/4588/

BUG: 916226
Change-Id: Id41ac17f467c37e7fd8863e0c19932d7b16344f8
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/4899
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>