Check resources are in expected states

This is the first step towards the blueprint stack-convergence.

Issue an update call with an additional flag (update_type=check) to
check that all resources are in their expected states.  If they are, the
call will complete with UPDATE_COMPLETE, otherwise resources will be
marked as UPDATE_FAILED with the corresponding reason.

blueprint stack-check
Change-Id: I4e39bfe6a3dca04305563844d5922da7e0bb67b3