Merge branch 'fc/transport-helper-error-reporting'

Update transport helper to report errors and maintain ref hierarchy used to keep track of remote helper state better. * fc/transport-helper-error-reporting: transport-helper: fix remote helper namespace regression test: remote-helper: add missing and t5801: "VAR=VAL shell_func args" is forbidden transport-helper: update remote helper namespace transport-helper: trivial code shuffle transport-helper: warn when refspec is not used transport-helper: clarify pushing without refspecs transport-helper: update refspec documentation transport-helper: clarify *:* refspec transport-helper: improve push messages transport-helper: mention helper name when it dies transport-helper: report errors properly