Fix parsing of extension metadata containing Unicode characters.
Review Request #10116 — Created Aug. 12, 2018 and submitted
If extension metadata contained any Unicode characters, we'd fail to
parse the metadata, hitting Unicode decoding errors. This was due to the
treatment of metadata as Unicode strings, but pkg_resources actually
returns these as bytestrings on both Python 2.x and 3.x.
We now process as bytestrings, and the tests have been updated to
represent metadata as bytestrings as well.
Unit tests pass.
Successfully ran Review Board with an extension containing Unicode
characters in the description.