[rancid] Cisco devices and calculating percent free

[Chris Wopat]

I recently updated to v3.13, I do not recall exactly what version I
was on but it was >1 year old, and could've been HEAD based on some
previous debugging of other issues.

Anyhow, we have many IOS devices that calculate percent free and it oscillates:

- !Flash: bootflash: 1 GB total (19% free)
+ !Flash: bootflash: 1 GB total (18% free)

Without manually patching ios.pm (or wherever this takes place) is
there any type of config setting to just turn off showing any info
about how much disk space is free? We get this info properly from snmp
trending systems.

Just trying to cut down on router diffs where there were no actual
config changes.

Cheers,
Chris