tests/test-hooklib-changeset_published.t

run-tests: stop ignoring venv-installed packages

This will allow test dependencies to be installed within a venv, instead of
tampering with sys/user sites.  One thing to note here is that the `VIRTUAL_ENV`
path takes precedence over system-site, unlike when run directly with an
activated `venv`.  For example, `sys.path` as viewed from a feature test in
`hghave.py`, when running `hghave vcr` directly with an activated `venv`:

    sys.path: [
        '/home/jenkins/hg-committed/tests',
        '/usr/lib/python38.zip',
        '/usr/lib/python3.8',
        '/usr/lib/python3.8/lib-dynload',
        '/home/jenkins/test_venv/lib/python3.8/site-packages'
    ]

vs `sys.path` from the same feature test, when run by `run-tests.py` with this
change:

    sys.path: [
        '/home/jenkins/hg-committed/tests',
        '/home/jenkins/hg-committed',
        '/home/jenkins/hg-committed/tests',
        '/home/jenkins/test_venv/lib/python3.8/site-packages',
        '/usr/lib/python38.zip',
        '/usr/lib/python3.8',
        '/usr/lib/python3.8/lib-dynload',
        '/home/jenkins/.local/lib/python3.8/site-packages',
        '/usr/local/lib/python3.8/dist-packages',
        '/usr/lib/python3/dist-packages'
    ]

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > notify =
  > hooklib =
  > 
  > [phases]
  > publish = False
  > 
  > [notify]
  > sources = pull
  > diffstat = False
  > messageidseed = example
  > domain = example.com
  > 
  > [reposubs]
  > * = baz
  > EOF
  $ hg init a
  $ hg --cwd a debugbuilddag .
  $ hg init b
  $ cat <<EOF >> b/.hg/hgrc
  > [hooks]
  > incoming.notify = python:hgext.notify.hook
  > txnclose-phase.changeset_published = python:hgext.hooklib.changeset_published.hook
  > EOF
  $ hg --cwd b pull ../a | "$PYTHON" $TESTDIR/unwrap-message-id.py
  pulling from ../a
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets 1ea73414a91b (1 drafts)
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Date: * (glob)
  Subject: changeset in * (glob)
  From: [e-mail]
  X-Hg-Notification: changeset 1ea73414a91b
  Message-Id: <hg.[e-mail]>
  To: [e-mail]
  
  changeset 1ea73414a91b in $TESTTMP/b
  details: $TESTTMP/b?cmd=changeset;node=1ea73414a91b
  description:
  	r0
  (run 'hg update' to get a working copy)
  $ hg --cwd a phase --public 0
  $ hg --cwd b pull ../a | "$PYTHON" $TESTDIR/unwrap-message-id.py
  pulling from ../a
  searching for changes
  no changes found
  1 local changesets published
  Subject: changeset published
  In-reply-to: <hg.[e-mail]>
  Message-Id: <hg.[e-mail]>
  Date: * (glob)
  From: [e-mail]
  To: [e-mail]
  
  This changeset has been published.
  $ hg --cwd b phase --force --draft 0
  $ cat <<EOF >> b/.hg/hgrc
  > [notify_published]
  > messageidseed = example2
  > domain = alt.example.com
  > template = Subject: changeset published
  >            From: [e-mail]\n
  >            This draft changeset has been published.\n
  > EOF
  $ hg --cwd b pull ../a | "$PYTHON" $TESTDIR/unwrap-message-id.py
  pulling from ../a
  searching for changes
  no changes found
  1 local changesets published
  Subject: changeset published
  From: [e-mail]
  In-reply-to: <hg.[e-mail]>
  Message-Id: <hg.[e-mail]>
  Date: * (glob)
  To: [e-mail]
  
  This draft changeset has been published.