Double border on CI status badges in build show page

I believe there is an issue in master, currently visible on dev: https://dev.gitlab.org/gitlab/omnibus-gitlab/commit/96b8f2b16fc5ca97a1036276d5ee827e12925546/builds

@ayufan The issue was actually questioned by @rspeicher in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2760#note_4238266 but not addressed.