Fix searching for groups
    
    It used to send you to a project if there was a project of the same name.
    This commit also makes the drop-down a little more coherent with the
    other search pages (and includes the group description).
    
    Relates to https://pagure.io/pagure/issue/2019
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>