wiki: clean up broken data if migration failed (#3792)
wiki: clean up broken data if migration failed (#3792)

chriswatt/gogs,gogits/gogs,cgars/gogs,psaavedra/gogs,psaavedra/gogs,gogits/gogs,Spice-King/gogs,Spice-King/gogs,mukaiu/gogs,xaionaro/gogs,pikacloud/pikacode,ForxaCoLab/forxa,psaavedra/gogs,mukaiu/gogs,xaionaro/gogs,linquize/gogs,chriswatt/gogs,linquize/gogs,pikacloud/pikacode,dancewing/gogs,liliexuan/gogs,dlob/gogs,dancewing/gogs,linquize/gogs,dlob/gogs,chriswatt/gogs,cgars/gogs,cgars/gogs,liliexuan/gogs,xaionaro/gogs,Spice-King/gogs,liliexuan/gogs,dancewing/gogs,pikacloud/pikacode,mukaiu/gogs,wangjild/gogs,dancewing/gogs,dlob/gogs,ForxaCoLab/forxa,wangjild/gogs,ForxaCoLab/forxa,wangjild/gogs,gogits/gogs