remove unneeded Relation#all from Group#user_removed
Rails4: replace deprecated find_all_by_* at WikiPageTest
remove unneeded Relation#all from WikiPage#handle_redirects
Rails4: replace deprecated find_all_by_* at WikiPage model
Rails4: replace deprecated Relation#update_all at Issue model
Rails4: replace deprecated Relation#update_all at IssueCategory model
Rails4: replace deprecated Relation#update_all at GroupTest
Rails4: replace deprecated Relation#update_all at Group model
Rails4: replace deprecated Relation#update_all at IssueTest
