If the virDomainDefPtr object has an 'id' of -1, then forcably
set the VIR_DOMAIN_XML_INACTIVE flag to ensure generated XML
does not include any cruft from the previously running guest
such as console PTY path, or VNC port.

* src/conf/domain_conf.c: Set VIR_DOMAIN_XML_INACTIVE if
  def->id is -1. Replace checks for def->id == -1 with
  check against flags & VIR_DOMAIN_XML_INACTIVE.