fix hound style

Author: Roy-Mao

lib/fcm/connection.rb

@@ -100,9 +100,7 @@ def build_not_registered_ids(body, registration_id)
       return not_registered_ids if body.empty?
       if body['failure'].positive?
         body['results'].each_with_index do |result, index|
-          if not_registered?(result)
-            not_registered_ids << registration_id[index]
-          end
+          not_registered_ids << registration_id[index] if not_registered?(result)
         end
       end
       not_registered_ids