[Ntop] Netflow Interfaces

[Jon Smith]

I added 32 interfaces, everything was fine until #32.  After adding it
and attempting to set the interface name I get the following from the
web interface:

"Netflow configuration error.  Unable to locate the specified device.
Please activate the plugin first."

And then ntop segfaulted and I got a kernel panic message in syslog.
I restarted ntop (started fine) and now when attempting to delete the
interfaces anytime I delete an interface with an ID >19 I get the same
error message.