Return process id of openvpn from interactive service to client

Return process id of openvpn from interactive service to client

- The process id is returned as a message formatted in the same manner
  as error messages from the service to the client: i.e., a three-line
  message with error number formatted as 0x%08x on line 1, followed by
  the PID in format 0x%08x on line 2 and a description that reads as
  "Process ID" on line 3. Error number is set to zero to indicate
  this is an informational message.

This provides a way for service clients to check the status of openvpn
and terminate it without needing management interface or exit event.
Useful when the interactive service is used from a launch script, or
to force-terminate openvpn from the GUI if/when needed.

v2 changes: format of the message changed as described above.

Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1466736656-27501-1-git-send-email-selva.nair@gmail.com>
URL: http://article.gmane.org/gmane.network.openvpn.devel/11984
Signed-off-by: Gert Doering <gert@greenie.muc.de>