Catch failed connection due to a bad region in ec2_scaling_policy

Fixes #7506

library/cloud/ec2_scaling_policy

@@ -162,6 +162,8 @@ def main():
 
     try:
         connection = connect_to_aws(boto.ec2.autoscale, region, **aws_connect_params)
+        if not connection:
+            module.fail_json(msg="failed to connect to AWS for the given region: %s" % str(region))
     except boto.exception.NoAuthHandlerFound, e:
         module.fail_json(msg = str(e))