protocol/server: Relax lktable finodelk del_locker check

Problem:
Client xlator issues finodelk using anon-fd when the fd is not
opened on the file. This can also happen between attempts to re-open
the file after client disconnects. It can so happen that lock is taken
using anon-fd and the file is now re-opened and unlock would come with
re-opened fd. This will lead to leak in lk-table entry, which also
holds reference to fd which leads to fd-leak on the brick.

Fix:
Don't check for fds to be equal for tracking finodelks.
Since inodelk is identified by (gfid, connection, lk-owner)
fd equality is not needed.

Change-Id: I62152d84caef0b863c973845e618076d388e6848
BUG: 993247
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/5499
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>