release-queue: port to python3
release-queue: port to python3

Also make the output reproducible from one run to another by sorting the
commits.

Change-Id: Icd39f2695de146ae820b54f0e6e232cbcfc47b09

Linaro/lava-server,Linaro/lava-server,Linaro/lava-server,Linaro/lava-server