Patch from Massimo Dal Zotto <dz@cs.unitn.it>

Patch from  Massimo Dal Zotto <dz@cs.unitn.it>

The first patch changes the behavior of aclcheck for groups. Currently an user
can access a table only if he has the required permission for ALL the groups
defined for that table. With my patch he can access a table if he has the
permission for ONE of the groups, which seems to me a more useful thing.
If you think this should be the correct behavior of the acl group check feel
free to remove the #ifdef, if not please add a commented line to config.h.