Fix formatting of mercurial revisions with Python 3.8
Review Request #11135 — Created Aug. 10, 2020 and submitted — Latest diff uploaded
In Python 3.8, attempting to use formatting on a bytestring with
dictionary parameters will end up looking for the keys as bytestrings
rather than unicode. This results in a KeyError. This change fixes it so
we do the format entirely asstrand then encode tobytes.
- Verified that the encoding worked correctly.
- Ran unit tests.