pullrequest: give up finding author when jgit can't find the first commit of a given path
pullrequest: give up finding author when jgit can't find the first commit of a given path

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