[gerrit] Fix encoding in ChangeEdit
[gerrit] Fix encoding in ChangeEdit

gerrit_util.ChangeEdit was passing the result of b64encode into a %s
format, which was printing the contents with a bytes prefix (b'...').

Decode the bytes object back to a str object before passing it to '%s'

Bug: v8:12849
Change-Id: I8b54b427bbbe8b914444d7486b5a8afbd743de70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3683382
Reviewed-by: Aravind Vasudevan <dbe94b625b74f03bb5e24a737a4f1e15753433de@google.com>
Commit-Queue: Aravind Vasudevan <dbe94b625b74f03bb5e24a737a4f1e15753433de@google.com>
Auto-Submit: Leszek Swirski <c4ae40685bdde089cbd28c35b297ca2c14b8b1bf@chromium.org>
Reviewed-by: Gavin Mak <bdcbd10822f2f5deecea3bf14d73e9025b1b8375@google.com>

CoherentLabs/depot_tools,CoherentLabs/depot_tools