Added setting of the health_check options on an existing ASG

library/cloud/ec2_asg

@@ -120,7 +120,8 @@ except ImportError:
     sys.exit(1)
 
 ASG_ATTRIBUTES = ('launch_config_name', 'max_size', 'min_size', 'desired_capacity',
-                     'vpc_zone_identifier', 'availability_zones')
+                     'vpc_zone_identifier', 'availability_zones',
+                     'health_check_period', 'health_check_type')
 
 def enforce_required_arguments(module):
     ''' As many arguments are not required for autoscale group deletion