py3 - ported ec2_vpc_route_table iterkeys to dict.keys() (#3503)

* ported ec2_vpc_route_table iterkeys to dict.keys() for py3

Addresses ansible/ansible#18507

* Removed '.keys()'

lib/ansible/modules/extras/cloud/amazon/ec2_vpc_route_table.py

@@ -298,7 +298,7 @@ def route_spec_matches_route(route_spec, route):
             if all((not route.gateway_id, not route.instance_id, not route.interface_id, not route.vpc_peering_connection_id)):
                 return True
 
-    for k in key_attr_map.iterkeys():
+    for k in key_attr_map:
         if k in route_spec:
             if route_spec[k] != getattr(route, k):
                 return False