Geo: Remove Gitlab::LfsToken::LegacyRedisDeviseToken implementation and usage
Context: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8044#note_122351185
Gitlab::LfsToken::LegacyRedisDeviseToken
is meant as a stop gap solution to assist in maintaining any git-lfs download requests that may already be in flight during a GitLab upgrade.