packaging: extract pre-computed version when running from plain tarball The tarballs created by setup.py are not including the usual archive markers that `hg archive` leaves, so the rewrite of the version number computation actually left the empty version string around. This meant that installations from PyPI would use 0.0.0 as version string. Differential Revision: https://phab.mercurial-scm.org/D10502

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init

  $ echo 'base' > base
  $ hg ci -Ambase
  adding base

  $ hg qnew -mmqbase mqbase

  $ hg qsave
  $ hg qrestore 2
  restoring status: hg patches saved state