add libvirt-python for libvirt package

This patch adds build prerequisites for libvirt

Change-Id: Iaa2251708616e9c69817bf5b346d795ea7a4d21b

bindep.txt

@@ -0,0 +1,7 @@
+# This is a cross-platform list tracking distribution packages needed for install and tests;
+# see https://docs.openstack.org/infra/bindep/ for additional information.
+
+# libvirt-dev is needed by libvirt library.
+libvirt-dev [platform:dpkg]
+python-libvirt [platform:dpkg]
+pkg-config [platform:dpkg]

tox.ini

@@ -95,3 +95,15 @@ deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt
   -r{toxinidir}/requirements.txt
+
+[testenv:bindep]
+# Do not install any requirements. We want this to be fast and work even if
+# system dependencies are missing, since it's used to tell you what system
+# dependencies are missing! This also means that bindep must be installed
+# separately, outside of the requirements files, and develop mode disabled
+# explicitly to avoid unnecessarily installing the checked-out repo too (this
+# further relies on "tox.skipsdist = True" above).
+basepython = python3
+deps = bindep
+commands = bindep test
+usedevelop = False