Make gethostbyaddr fail with ECANCELLED for ares_cancel()

When `ares_cancel()` was invoked, `ares_gethostbyaddr()`
queries would fail with `ENOTFOUND` instead of `ECANCELLED`.

It seems appropriate to treat `ares_cancel()` like `ares_destroy()`,
but I would appreciate review of the correctness of this change.

Ref: nodejs/node#14814

ares_gethostbyaddr.c

@@ -157,7 +157,7 @@ static void addr_callback(void *arg, int status, int timeouts,
         }
       end_aquery(aquery, status, host);
     }
-  else if (status == ARES_EDESTRUCTION)
+  else if (status == ARES_EDESTRUCTION || status == ARES_ECANCELLED)
     end_aquery(aquery, status, NULL);
   else
     next_lookup(aquery);