Fixed bug - milestone delete.
Fixed bug - milestone delete.

oolso/yobi,bloodybear/yona,oolso/yobi,violetag/demo,doortts/forked-for-history,oolso/yobi,doortts/forked-for-history,brainagenet/yobi,doortts/forked-for-history,brainagenet/yobi,doortts/fork-yobi,doortts/fork-yobi,ahb0327/yobi,ihoneymon/yobi,ahb0327/yobi,yona-projects/yona,ihoneymon/yobi,yona-projects/yona,ahb0327/yobi,brainagenet/yobi,doortts/fork-yobi,naver/yobi,Limseunghwan/oss,bloodybear/yona,Limseunghwan/oss,naver/yobi,naver/yobi,ihoneymon/yobi,bloodybear/yona,violetag/demo,bloodybear/yona,ChangsungKim/TestRepository01,yona-projects/yona,doortts/fork-yobi,yona-projects/yona,ChangsungKim/TestRepository01,Limseunghwan/oss