Fix final line in EmailsOnPush email diff being rendered as error.
Fixes https://github.com/gitlabhq/gitlabhq/issues/8976 and private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2194.
Pulls in gitlab_git 7.1.5, which includes https://gitlab.com/gitlab-org/gitlab_git/merge_requests/18.