Add disco-stein bundle to gate tests

The bundle disco-stein was in the dev bundles because
a bug with the Python 3.7 syntax prevented the success of
the deployment of HA clusters. This bug is fixed, we can
reintegrate disco-stein in the gate bundles.

Other small additions:
- removing sitepackages in tox.ini to avoid test env pollution
- skip_missing_interpreters in tox.ini set to False to avoid false
positives by skipping missing interpreters.

LP Related-Bug: #1823718

Change-Id: Ie3d970ffde85b8f447ec7d2a95041ef59a747d8c

src/tests/gate-basic-disco-stein

@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+
+"""Amulet tests on a basic barbican deployment on disco-stein."""
+
+from basic_deployment import BarbicanBasicDeployment
+
+if __name__ == '__main__':
+    deployment = BarbicanBasicDeployment(series='disco')
+    deployment.run_tests()
+

src/tox.ini

@@ -4,6 +4,10 @@
 [tox]
 envlist = pep8
 skipsdist = True
+# NOTE(beisner): Avoid build/test env pollution by not enabling sitepackages.
+sitepackages = False
+# NOTE(beisner): Avoid false positives by not skipping missing interpreters.
+skip_missing_interpreters = False
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}

src/wheelhouse.txt

@@ -0,0 +1,3 @@
+
+jinja2
+psutil

tox.ini

@@ -4,7 +4,10 @@
 [tox]
 skipsdist = True
 envlist = pep8,py37
-skip_missing_interpreters = True
+# NOTE(beisner): Avoid build/test env pollution by not enabling sitepackages.
+sitepackages = False
+# NOTE(beisner): Avoid false positives by not skipping missing interpreters.
+skip_missing_interpreters = False
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}