Fix issue for policies not loading on GUI push tab

Fix issue for policies not loading on GUI push tab

	- found the problem to be with a line of code to add all the
	scopes from the role to a Set of scopes.  when the scopes
	attribute in the role object is null it logs an exception and
	fails to load policies.  I added a new method to check the value
	of the roles.getScopes() for null and only attempt to add the
	scope to the set if it is not null

	- I created a separate method to do this in order to avoid an
	increase in technical debt as it would have added to the
	complexity if I kept it in the same method.

	- PATCH 4: Added scopes to the method arguments in order to
	avoid overwriting scopes that are added in prevous interations
	of the loop.

	- PATCH 5: removed redundant scopes assignment per Jorge's
	review.

Change-Id: Ifcc8775d3db8ecc722ee6806310a58ecb4e15856
Issue-ID: POLICY-1981
Signed-off-by: Michael Mokry <michael.mokry@att.com>