Bump vcap_common

git shortlog e5d71831a19f9a59cf757b4e2bd25b2af32f1611..HEAD
CloudFoundry Services Team (1):
      Merge pull request #2 from SlimYang/master

David Stevenson and Matt Royal (1):
      Added optional unique_id as part of a service offering & provision

Jesse Zhang and Scott Calvert (1):
      Add CreateSnapshotV2Request JsonMessage

Yang Yang (1):
      add message for service update handle in v2 api