Since 1.11.0, our releases have been getting tagged after branching. So calc_release_version.py, when run from a non-master, non-release branch, will return something of the form: 1.11.1-20190813+git0fd1e4e8a4

Let's consider instead changing this to be something that clearly indicates this is not a release version (e.g. 0.0.<git hash>) or throwing an error.