TOOLS: sss_groupshow fails to show MPG
    
    The MPG search uses it's own search function
    that used sysdb operation with shortname,
    but it expects internal fqname.
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/3184
    
    Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>