Remove incorrect assertion for MoveResizeTo

This caused gcc to assume the user never specifies a desktop by number,
which was not very helpful. Please crash when reaching an assert,
thanks.

openbox/actions/moveresizeto.c

@@ -118,7 +118,7 @@ static gboolean run_func(ObActionsData *data, gpointer options)
         case PREV_MONITOR:
             mon = (cmon == 0) ? (screen_num_monitors - 1) : (cmon - 1); break;
         default:
-            g_assert_not_reached();
+            /* desktop specified by number */
         }
 
         area = screen_area(c->desktop, mon, NULL);