Add flag to always close previous roll + minor refactor

The --close-previous-roll makes it possible to always
close a previously created roll when creating a new one.
This way it will be possible to avoid getting a pile of
open CLs created and never closed for all failed
roll attempts, which is useful for automation.

I also moved some variables out of the AutoRoller
class that doesn't neeed to be there.

BUG=chromium:433305
TESTED=Ran:
tools/autoroller/roll_webrtc_in_chromium.py --verbose --close-previous-roll
and verified it actually closed an existing roll.

R=tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/40349004

Cr-Commit-Position: refs/heads/master@{#8726}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8726 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed