fix to undo unix group name changes applied in v0.4.4

Reverts to make_shadow_compatible from version 0.4.3 and tries to undo any side-effects of using version 0.4.4:

• group names shortened with v0.4.4 are renamed to the name given by the current make_shadow_compatible
• however, if both groups already exist, this is logged for an admin to manually merge the two groups (since they first need to make sure that file ownership is transferred from the old to the new group)

The reason for doing this on user action is because we do not store the original group name from the userinfo.