Bad logic introduced while limiting logged warnings in entity.cgi

[jonstout]

Logic introduced here had the side effect of limiting some interfaces from being returned in entity.cgi?method=get_entities. The removed interfaces are those with ACLs containing no workgroup restrictions (an undef workgroup_id).

This line is incorrect:
https://github.com/GlobalNOC/OESS/blob/master/frontend/webservice/entity.cgi#L477

The correct logic should be:

next if (defined($acl->{'workgroup_id'}) && $acl->{'workgroup_id'} != $workgroup_id);