When running with Py3 we compare a byte string to a unicode string
when parsing StatsD metrics. This patch adds some unit tests to
reproduce the bug and decodes the bytestring to make the existing
comparisons valid under Py3. When backporting to Train we can use
Oslo encodeutils. Clearly we could have more unit tests, but
this makes a start.
Change-Id: I6341f96f5c186428d2d829cabf618a6f84f40ce2
Story: 2007684
Task: 39796
a2400fcf12