Allow bootstrap.py --repo=$REPO=$BRANCH:$COMMIT

[ixdy]

--repo=$REPO --branch=$BRANCH:$COMMIT was already supported.

See #2731 for discussion.

/assign @fejta @krzyzacy

[krzyzacy]

/lgtm

makes sense, not sure why it's originally disabled though @fejta

[fejta]

Hmm... Probably because --repo=master:deadbeef --pull=1234 will do weird stuff, aka not actually do what you want.

So maybe ensure this format doesn't use --branch or --pull?

[fejta]

/lgtm btw

[ixdy]

Updated logic so something like --repo=something=branch:commit --pull=123 is disallowed, since that case doesn't work and isn't worth fixing. (If you want that, just use the new repo syntax.)

[ixdy]

unit tests pass, please take one last look?

[krzyzacy]

lgtm still