FindRefName RPC now mandatory
FindRefName RPC now mandatory

Has never been in OPT_OUT, dispite being ages old. The time where
feature flags are still set by env vars.

Closes https://gitlab.com/gitlab-org/gitaly/issues/221

stoplightio/gitlabhq,jirutka/gitlabhq,iiet/iiet-git,dreampet/gitlab,jirutka/gitlabhq,dreampet/gitlab,mmkassem/gitlabhq,axilleas/gitlabhq,stoplightio/gitlabhq,jirutka/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,axilleas/gitlabhq,dreampet/gitlab,jirutka/gitlabhq,iiet/iiet-git,mmkassem/gitlabhq,iiet/iiet-git,axilleas/gitlabhq,dreampet/gitlab,stoplightio/gitlabhq,iiet/iiet-git,mmkassem/gitlabhq