Mouse navigation: change unnecesary warnings to messages

sent when trying to set rotation center without an object under the cursor and can be annoying if report view is set to show with warnings.

src/Gui/GestureNavigationStyle.cpp

@@ -1010,7 +1010,7 @@ void GestureNavigationStyle::onSetRotationCenter(SbVec2s cursor){
     SbBool ret = NavigationStyle::lookAtPoint(cursor);
     if(!ret){
         this->interactiveCountDec(); //this was in original gesture nav. Not sure what is it needed for --DeepSOIC
-        Base::Console().Warning(
+        Base::Console().Message(
             "No object under cursor! Can't set new center of rotation.\n");
     }