[rancid] Filtering out flash dir and time change events

[heasley]

Thu, Jul 27, 2017 at 08:29:55PM +0000, Walker, Alan:
> Thank you all for the suggestions.
> 
> I looked into disabling the timestamps with the "terminal exec prompt timestamp" command but this is only supported on some of my devices, and on those devices it was already disabled so I don't think that is related to the changes I'm seeing reported by Rancid.

because cisco is so awesome, the command changed at ~xr 3.8.

terminal no-timestamp
vs
terminal exec prompt no-timestamp

rancid runs both of these before a collection.  again, i'll point you
toward the alpha version.