copybot: Fix list initialization

BUG=None
TEST=./copybot.py --topic android-downstream --label Verified+1 --re nvaccaro@google.com --re subratabanik@google.com --merge-conflict-behavior ALLOW_CONFLICT --keep-pseudoheader Cq-Depend --keep-pseudoheader Change-Id --push-option 'uploadvalidator~skip' --push-option nokeycheck --ht '' --ht '' --upstream-history-limit 5 --downstream-history-limit 1000 --add-pseudoheader 'Cr-Build-Id: 8740269368728257329' --add-pseudoheader 'Cr-Build-Url: https://cr-buildbucket.appspot.com/build/8740269368728257329' --add-pseudoheader 'Copybot-Job-Name: android-brya-vboot_reference-copybot-downstream' --dry-run https://chromium.googlesource.com/chromiumos/platform/vboot_reference:firmware-android-15949.B https://chromium.googlesource.com/chromiumos/platform/vboot_reference:firmware-android-brya-14505.782.B:

Change-Id: Iea69a1b2e18fba31d69b252b9fb50e079cc07d4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/5792013
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Jonathon Murphy <jpmurphy@google.com>
Tested-by: Jonathon Murphy <jpmurphy@google.com>
1 file changed