pullrequest: Fix a bug that merging never stops
pullrequest: Fix a bug that merging never stops

A PersistenceException may occur while merging if there is a commit
whose message is longer than 2,000 because commit_message column's type
is varchar(2000).

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