Increase volume created checking retries to 60

In some cases 30 retries with 1 sec interval is not enough for
volume to be created.
Increased max tries to 60

Fixes bug 1213953

Change-Id: I6bcd395a4bac940387384cc85691d7219cf90e63
Fix use of bare list/dict types in instance_group object

The instance_group object was merged before we had helpers for
dict and list objects of strings. This makes that object use those
for schema safety.

Change-Id: I1f68e43a83f140f7b29b17c0961b267e64e48390
Closes-bug: 1221383
Merge "Increase volume created checking retries to 60"
Merge "Fix use of bare list/dict types in instance_group object"