Fixes#6861.
_venv_common.py is no longer executable. The reason for this is the venv creation logic is now different between Python 2 and Python 3. We could add code that branches on the Python version running the script, but I personally think that's unnecessary.
--setuptools and --no-site-packages is no longer passed to virtualenv either. These flags were made noops in virtualenv 1.10 and 1.7 respectively, but all of CentOS 6, 7, Debian 8+, and Ubuntu 14.04+ have new enough versions of virtualenv where these flags are no longer necessary. They are not even accepted as flags to Python 3's venv module.
Use of VENV_ARGS from test_sdists.sh was also removed because that environment variable hasn't done anything in a while.
I ran test farm tests on test_apache2.sh and test_sdists.sh with these changes and they passed.
* Fixes#6861.
* _venv_common is no longer executable.
* prevent regressions of #5082
* Fix test_leauto_upgrades.sh
test_leauto_upgrades.sh has been incorrectly been succeeding because while peep
doesn't work with newer versions of pip and letsencrypt-auto would crash,
the output included the version number so we reported the test as passing.
This updates letsencrypt-auto to the oldest version that still works for the
purpose of the test and sets pipefail so errors are properly reported.
* Test symlink creation in test_leauto_upgrades.sh
* Pin dependencies in test_sdists.sh.
* Fix permissions errors in test_tests.sh
* add get_certbot_version.sh
* Use get_certbot_version.sh in build.py
* make test_leauto_upgrades.sh more robust
* auto upgrades break tests
* OCSP experimental is not needed anymore
* Add test_sdists.sh
* Use LE_AUTO_VERSION, not repo version
* install OS deps earlier
* use readlink not realpath
* undo changes to build.py
* Factor out version code from build.py
* Use version.py in test_sdists
* Remove get_certbot_version
* workaround setuptools breakage
