features/quota: prevent statfs frame-loss when an error happens during

features/quota: prevent statfs frame-loss when an error happens during
ancestry building.

We do quota_build_ancestry in function 'quota_get_limit_dir',
suppose if quota_build_ancestry fails, then we don't have a
frame saved to continue the statfs FOP and client can hang.

Change-Id: I92e25c1510d09444b9d4810afdb6b2a69dcd92c0
BUG: 1178619
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Signed-off-by: vmallika <vmallika@redhat.com>
Reviewed-on: http://review.gluster.org/9380
Tested-by: Gluster Build System <jenkins@build.gluster.com>