Robot: Migrate NULL to nullptr.
Robot: Migrate NULL to nullptr.

ApolloAuto/apollo,wanglei828/apollo,jinghaomiao/apollo,ApolloAuto/apollo,ycool/apollo,wanglei828/apollo,jinghaomiao/apollo,ApolloAuto/apollo,ycool/apollo,jinghaomiao/apollo,xiaoxq/apollo,jinghaomiao/apollo,ApolloAuto/apollo,wanglei828/apollo,xiaoxq/apollo,ApolloAuto/apollo,xiaoxq/apollo,wanglei828/apollo,wanglei828/apollo,xiaoxq/apollo,jinghaomiao/apollo,xiaoxq/apollo,jinghaomiao/apollo,ApolloAuto/apollo,ycool/apollo,xiaoxq/apollo,ycool/apollo,ycool/apollo,ycool/apollo,wanglei828/apollo