MapOptimizer: fixed a crash when optimizing a global map received
MapOptimizer: fixed a crash when optimizing a global map received

jian-li/rtabmap_ros,introlab/rtabmap_ros,introlab/rtabmap_ros,introlab/rtabmap_ros,jian-li/rtabmap_ros,willdzeng/rtabmap_ros,introlab/rtabmap_ros,willdzeng/rtabmap_ros,jian-li/rtabmap_ros,Notou/rtabmap_ros,willdzeng/rtabmap_ros,Notou/rtabmap_ros,Notou/rtabmap_ros