error auth'ing with email as username

I believe I found a bug making it impossible to authorize against LDAP when using an email address as the username.

The bug is in _ldapauth_check_ldap() on line 925

The function does a few things to separate the username from server in an email, putting the name into the variable $login_name. However at the end of the function when ldapauth_auth() is called, it passes the variable $name, not $login_name.

Patch attached.