[rancid] Ignore updates to "AC Revision" for Cisco uBR7200

[Kenneth Lind]

Using Rancid current installation of 2.3.6 and having problems removing
notifications for the results of "show env all" for a Cisco uBR7200 and the
resulting cycling of reported power supply revisions such as:

!Power: Power Supply 1 is AC Revision F0. Unit is on.
!Power: Power Supply 2 is AC Revision F0. Unit is on.

Revisions randomly cycle between "F0" and "E0" and is not considered
alarming or worthy of notifications from Rancid.

Previous steps taken to hush the notifications involved editing
control_rancid to attempt post config captures from notifying.

Approximately line 449 in control_rancid changed from:
cvs -f diff -U 4 -ko | sed -e '/^RCS file: /d' -e '/^--- /d' \
    -e '/^+++ /d' -e 's/^\([-+ ]\)/\1 /' >$TMP.diff

Changed to:
cvs -f diff -U 4 --ignore-matching-lines='AC Revision' | sed -e '/^RCS
file: /d' -e '/^--- /d' -e '/^+++ /d' -e 's/^\([-+ ]\)/\1 /' >$TMP.diff

Results did not function as expected and Rancid continued to notify on
changes to "AC Revision." Further attempted to change same lines above with
use of wildcards, but doing so removed all notifications:
cvs -f diff -U 4 --ignore-matching-lines='*AC Revision*' | sed -e '/^RCS
file: /d' -e '/^--- /d' -e '/^+++ /d' -e 's/^\([-+ ]\)/\1 /' >$TMP.diff

Ultimate goal: do not capture the changes for versioning/differs to the "AC
Revision" updates for particular model devices while maintaining use of the
sub ShowEnv in rancid file.

Suggestions?