ec: Fix memory leak caused by undestroyed fops

Operations processed by ec_dispatch_one() were not correctly
completed by ec_complete(), leaving some structures in memory.

Now ec_complete() also calls ec_resume() for this type of fops.

This is a backport of http://review.gluster.org/8896/

Change-Id: Iaf0f2e8227399ebb735db9f1bd007593e0ece041
BUG: 1148521
Signed-off-by: Xavier Hernandez <xhernandez@datalab.es>
Reviewed-on: http://review.gluster.org/8897
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>