get-pick-list.sh: Include commits mentionining "CC: mesa-stable..." in pick list

get-pick-list.sh: Include commits mentionining "CC: mesa-stable..." in pick list

We recently adopted a new convention that patches can be nominated for the
stable branch by including a line in the commit message as follows:

	CC: mesa-stable@lists.freedesktop.org
This is a convenient syntax as "git send-email" will notice this line and
automatically copy the resulting patch email to the mesa-stable mailing list.

Here we extend the regular expression in the get-pick-list.sh script to also
notice this pattern, (as well as the traditional "NOTE: This patch is a
candidate..." form.