This reverts commit 13e37a3e.

Auth.find was a very generic name for a very specific method.
Auth.find_in_gitlab_or_ldap was inaccurate in GitLab EE where it also
looks in Kerberos.

-calling build_user will now apply defaults and only override them if as: :admin is set

Change-Id: Id1d938c0967752ecc14370af54f2d88128d18c44

“Can create groups” and “Can create teams” had hardcoded defaults to
`true`. Sometimes it is desirable to prohibit these for newly created
users by default.

fix: https://github.com/gitlabhq/gitlabhq/issues/1620

Should no longer freak out when omniauth settings aren't present in
gitlab.yml. People who aren't using it shouldn't even have to put a
'false' entry in their config for it (and probably wouldn't, after an
upgrade).