[rancid] fix for cisco c6k sup32s

[Lee]

Can I get an additional command added to the next version of rancid?

The Cisco c6k SUP32s have a sup-bootdisk: device and the current
version of rancid doesn't show the files on that device.  Fix is a
single line
   {'dir /all sup-bootdisk:'       => 'DirSlotN'},
added to commandtable in rancid.

Have I mentioned lately how much I love rancid?  We had a problem on a
sup720 where the boot device disappeared.  It took me maybe an hour to
create a script to check that the first "boot system xxx" file
actually exists on all devices[*] and find the same problem on a SUP32

Thanks,
Lee


* all but the nexus4000s.  They don't like a "dir /all bootflash:" and
I haven't figured out why rancid can't grab the config if they're
defined as a "cisco-nx" device type