Fix KeyError exception on check_deprecated_parameters
Fix KeyError exception on check_deprecated_parameters

heat_resource_tree_params is returning a KeyError.
Probably this was not caught before because it always had this key.
If the key doesn't exist, returning a empty dictionary because of
several for loops used and NoneType is not iterable.

Change-Id: I745c43b8b4461ae2f60834a262ab358a7434efeb
Closes-Bug: #1866184

openstack/python-tripleoclient