remote-viewer: Pass guri to remote_viewer_session_connected
    
    When connecting to a VM via oVirt instance, the original uri can not be
    retrieved using virt_viewer_session_get_uri(). Consequently, it was
    never saved, even though the connection succeeds and the actual callback
    for "session-connected" signal, which saves the URI, is invoked.
    
    To solve this problem, we always pass a copy of the guri as user-data
    parameter for the callback, and if the call to
    virt_viewer_session_get_uri() returns NULL, the parameter is used
    instead.
    
    Resolves: https://bugzilla.redhat.com/1459792
    
    Signed-off-by: Eduardo Lima (Etrunko) <etrunko@redhat.com>
    Acked-by: Victor Toso <victortoso@redhat.com>