Changed behavior of deregister. If an instance is not found in the ELB then…

Changed behavior of deregister.  If an instance is not found in the ELB then simply return 'changed=false'.  Otherwise always remove the instance from the ELB no matter what state its currently in.

library/cloud/ec2_elb

@@ -129,18 +129,20 @@ class ElbManager:
 
         for lb in self.lbs:
             initial_state = self._get_instance_health(lb) if wait else None
-
-            if initial_state and initial_state.state == 'InService':
-                lb.deregister_instances([self.instance_id])
-            else:
+            if initial_state is None:
+                # The instance isn't registered with this ELB so just 
+                # return unchanged
                 return
 
+            lb.deregister_instances([self.instance_id])
+
+            # The ELB is changing state in some way. Either an instance that's
+            # InService is moving to OutOfService, or an instance that's
+            # already OutOfService is being deregistered.
+            self.changed = True
+
             if wait:
                 self._await_elb_instance_state(lb, 'OutOfService', initial_state, timeout)
-            else:
-                # We cannot assume no change was made if we don't wait
-                # to find out
-                self.changed = True
 
     def register(self, wait, enable_availability_zone, timeout):
         """Register the instance for all ELBs and wait for the ELB