ec2_elb_facts: fix errors with no names input (#3381)

* None being passed around results in a Bad Time (tm)

* need to return the full set of elbs for an empty list

* logic is hard

lib/ansible/modules/extras/cloud/amazon/ec2_elb_facts.py

@@ -203,16 +203,19 @@ class ElbInformation(object):
             self.module.fail_json(msg = "%s: %s" % (err.error_code, err.error_message))
 
         if all_elbs:
-            for existing_lb in all_elbs:
-                if existing_lb.name in self.names:
-                    elb_array.append(self._get_elb_info(existing_lb))
-
-        return elb_array
+            if self.names:
+                for existing_lb in all_elbs:
+                    if existing_lb.name in self.names:
+                        elb_array.append(existing_lb)
+            else:
+                elb_array = all_elbs
+                    
+        return list(map(self._get_elb_info, elb_array))
 
 def main():
     argument_spec = ec2_argument_spec()
     argument_spec.update(dict(
-            names={'default': None, 'type': 'list'}
+            names={'default': [], 'type': 'list'}
         )
     )
     module = AnsibleModule(argument_spec=argument_spec)