#1 fix the (require-)group directive

[Olivier Berger]

The following patch, written by my colleague Benoit
Hamet applies the same fix that was done for the user
directive to the group directive.

Actually, several applications can use the LDAP groups
using the username as the member uid instead of the
full DN.

This patch allows us to use mod_ldap for mixing
phpgroupware, apache, mod-dav together on LDAP based
authentication and group membership for access lists.

[Olivier Berger]