Enforce credentials requirement on stack create/update.

Credentials need to be supplied whenever they are stored with the stack,
which is during stack create and update.

Some users have been relying on their auth token to perform all heat
operations (as all other openstack services support) however this has
led them to experience obscure errors when wait handles or alarms are
triggered.

Failing early with a clear error message will stop this class of errors.

Fixes bug: #1194303

Change-Id: I3edef3dee843bb06760be6294b798761eba30cb8
Check duplicate names between params and resources

make sure there are no duplicate logical names across parameter
and resource definitions

Fixes bug #1196491

Change-Id: I353b84dd8b9bfe77b214e93cc9f1a080ebe2248b
Merge "Enforce credentials requirement on stack create/update."
Merge "Check duplicate names between params and resources"