tests/test-check-pyflakes.t

packaging: rework version detection and declaration (issue4912)

Previously the -rc in our rc tags got dropped, meaning that those
packages looked newer to the packaging system than the later release
build. This rectifies the issue, though some damage may already have
been done on 3.6-rc builds.

I'm mostly cargo-culting the RPM version format - there don't appear
to be rules for RPM about how to handle this. Hopefully an RPM
enthusiast can fix up what I've done as a followup.

#require test-repo pyflakes

  $ cd "`dirname "$TESTDIR"`"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ hg locate 'set:**.py or grep("^!#.*python")' 2>/dev/null \
  > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"
  tests/filterpyflakes.py:58: undefined name 'undefinedname'