kolla-build: Wrap tpl_dict.keys() in a list()
kolla-build: Wrap tpl_dict.keys() in a list()

In python 3, tpl_dict.keys() returns a dict_keys object that does not
support indexing and is then indexed.
Wrap tpl_dict.keys() in a list() so it can be be indexed in python 2 and
3.

Change-Id: I17e3bbfc4eeba58e4bdd7fdd1ecdb21baa5c4461
Closes-Bug: 1778781

stackforge/kolla,rahulunair/kolla,openstack/kolla,stackforge/kolla,rahulunair/kolla,stackforge/kolla,openstack/kolla