[rancid] ignoring toggling/changing output lines

Dear All

As much as I love RANCID I am fighting with two anoyances which I, at
the moment, have no ideas how to fix them.

The first one I do not seem to be the only one beeing hit by: changing
type 7 passwords within l2tp-class-sections on Cisco routers. As from
what the archives say this is probably even expected behaviour according
to TAC. Changesets look something like this:
--snip
  l2tp-class NAME
   hidden
   authentication
-  password 7 abcabcabcabcabcabc
+  password 7 xyzxyzxyzxyzxyzxyz
  !
--snap

To be honest: I would be glad with a solution that simply ingores the
password, but only the l2tp-class one. I would like to keep the other
passwords in the config. Any ideas?

The second issue involves Brocades (former Foundry Networks) Metro Ring
Protocol. You have to specify two interfaces which are defining the east
and west side of the ring as from this boxes perspective. Sure, they
might change if a break in the ring happens. But I am seeing toggling
between these interfaces way more than we have ring-breaks...

A typical output of such a changeset would look like this:
--snip