LDAP user filter is broken in GitLab CE 6.9.1

The commit in !79 (merged) broke the LDAP user filter because GitLab's LDAP user filters are not compatible with the format expected by omniauth-ldap: omniauth-ldap expects you to include the username into the filter using a format string.

Example GitLab LDAP user filter: (memberOf=cn=foo,dc=bar)

Example omniauth-ldap user filter: (&(uid=%{username})(memberOf=cn=foo,dc=bar)).

We are working on a fix.