add support for ccng to return a url for upload snapshot

Change-Id: I88924fb36c99d8a542efa08c436c75560367b0b8
Unify label_and_version in legacy_service_gateway apis

Change-Id: I39e9a12aad934367a54d090e8027a88ffd4e12f0
Merge pull request #8 from cloudfoundry/sean_1

add support for ccng to return a url for upload snapshot
Merge pull request #5 from mflu/master

Unify label_and_version in legacy_service_gateway apis