Update volume-type's quota when extending volume

Now cinder only update total "gigabytes" quota but not update special
volume-type's "gigabytes" quota.

Fix bug #1375120

Change-Id: Ibb0b91afc81ba8c864f3c56fbe8a31972edd9bfc
Signed-off-by: Haomai Wang <haomai@unitedstack.com>