Copter: move MSG_BATTERY2 higher in select

No functional change

ArduCopter/GCS_Mavlink.pde

@@ -616,6 +616,11 @@ bool GCS_MAVLINK::try_send_message(enum ap_message id)
 #endif // MOUNT == ENABLED
         break;
 
+    case MSG_BATTERY2:
+        CHECK_PAYLOAD_SIZE(BATTERY2);
+        gcs[chan-MAVLINK_COMM_0].send_battery2(battery);
+        break;
+
     case MSG_OPTICAL_FLOW:
 #if OPTFLOW == ENABLED
         CHECK_PAYLOAD_SIZE(OPTICAL_FLOW);
@@ -644,11 +649,6 @@ bool GCS_MAVLINK::try_send_message(enum ap_message id)
 
     case MSG_RETRY_DEFERRED:
         break; // just here to prevent a warning
-
-    case MSG_BATTERY2:
-        CHECK_PAYLOAD_SIZE(BATTERY2);
-        gcs[chan-MAVLINK_COMM_0].send_battery2(battery);
-        break;
     }
 
     return true;