Let packagers_without_bugzilla ignore some namespaces
    
    Pagure supports enforcing group membership on some namespaces
    only. So for example on src.fp.o users must be in the packager
    group to be added to projects on the rpms or the modules
    namespaces. However, this requirement does not apply for project
    in the "tests" namespace.
    So when checking if packager have a valid bugzilla account, we can
    (and should) ignore these namespaces.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>