Redesigned sign in form breaks with LDAP enabled

Summary

It looks like the sign in form was recently redesigned - in https://gitlab.com/gitlab-org/gitlab-ce/issues/13937 and https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6328. With LDAP enabled, the form breaks (see screenshots)

Steps to reproduce

Enable ldap in gitlab.yml.

Expected behavior

Form renders nicely

Actual behavior

For renders with LDAP and Standard tab, but the form has some strange elements and the sign up is also visible on the LDAP tab.

Screenshots

without LDAP:

with LDAP: