session: don't close outside connections during session reset
    
    If a user clicks cancel in the login screen the underlying
    user verification session gets reset, which causes the greeter
    connection to get scrubbed from the record.
    
    Resetting is correct, but scrubbing the connection isn't.
    
    The bug manifests itself at login time, by the greeter not fading
    out if the user hit cancel once before logging in.  Instead, the
    greeter gets kill right away and login proceeds abruptly.
    
    This commit makes gdm_session_reset not erreoneously do this connection
    scrubbing.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=703386