Snapshot reservation sync calls wrong resource.

The snapshot reservations code isn't calling the
correct resource on sync (it's calling volumes).  There's
also some problems with the logic being used on the delete/clean up
that are fixed here as well.

Fixes bug: 1157506
Fixes bug: 1157982

Change-Id: I91327b8043ab63aa35ea8a91b6de544bf5bf6c61
Fetch volume_types by uuid and not by name in v2

Change-Id: I02cc035565f9496cd5af228c55ced5cafef2ad81
Fixes: bug #1087817