This commit makes several changes to `tag-release.sh` according to the
change in release process:
1. It will support a "ON_RELEASE_BRANCH" param passed via env variable.
When it's set to "TRUE". The release will be created on the commit of
branch like `release-xxx`. This enables us to create release branch
before GA and tag RC release.
2. It removes the code to push a new branch to upstream. This is
because we decided to create branch manually. For patch releases, we
will not push the change to release branch, instead, we will make
sure the release branch has all commits cherrypicked BEFORE we run
this script to tag the release.
After the change the script will focus on only tag the release, not
making other code change to release branches.
Signed-off-by: Daniel Jiang <jiangd@vmware.com>
d08c4bae4d