libglusterfs/syncop: implement inodelk

Change-Id: Iea489157490b70cb2bb03576b0d4943c6d8f052d
BUG: 1138395
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-on-master: http://review.gluster.org/8522
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Reviewed-on: http://review.gluster.org/8610