network: better log message when network is inactive during reconnect
    
    If the network isn't active during networkNotifyActualDevice(), we
    would log an error message stating that the bridge device didn't
    exist. This patch adds a check to see if the network is active, making
    the logs more useful in the case that it isn't.
    
    Partially resolves: https://bugzilla.redhat.com/1442700