proto_sched: fix a compile warning (regression of 8dd0e0f70f)
proto_sched: fix a compile warning (regression of 8dd0e0f70f)

scalaris-team/scalaris,scalaris-team/scalaris,jvf/scalaris,jvf/scalaris,caijieming-baidu/scalaris,caijieming-baidu/scalaris,caijieming-baidu/scalaris,scalaris-team/scalaris,scalaris-team/scalaris,scalaris-team/scalaris,jvf/scalaris,caijieming-baidu/scalaris,jvf/scalaris,caijieming-baidu/scalaris,caijieming-baidu/scalaris,scalaris-team/scalaris,scalaris-team/scalaris,jvf/scalaris,jvf/scalaris,scalaris-team/scalaris,jvf/scalaris,caijieming-baidu/scalaris