patch for mrtg configuration changes XCF-2348

http://track.sipfoundry.org/browse/XCF-2348

Andrei:
This is a nice improvement over hard coded values of the original 
configuration. I was thinking we could get even better though:

- as Scott suggested in his e-mail 
(http://thread.gmane.org/gmane.comp.voip.sipx.devel/8351/focus=8661) the 
wrapper script should not be started by sipXconfig but by our process 
manager. You can probably check what he has done for callresolver-agent 
integration (all it requires is a that sipxconfig-mrtg RPM installs a 
proecess descriptor in /etc/sipxpbx/process.d there are many examples 
there. I think if you do that, the init script might be much simpler (or 
not needed at all) since it would not have to do everything that 
watchdog is doing already (for example dealing with PID files).

- not sure if MRTG configuration ends up in the process place: I think 
it should be somewhere in {prefix}/etc/sipxpbx and not in {prefix}/var/mrtg

Also the configuration for this service should be pushed through 
replication and not written directly to the disk. But that can be fixed 
as separate issue.

What do you think?
D.