tests: force an English UTF-8 locale

Various checks in the test suite try to match for error/status messages,
so using a localized libvirt (or even using translations of an installed
version of virt-manager in the system) makes those check fail.
Hence, force (using $LANG, and unsetting $LANGUAGE) an English UTF-8
locale.

Thanks Cole Robinson for spotting the right place where to inject the
locale settings.

Fixes: #199

Signed-off-by: Pino Toscano <ptoscano@redhat.com>

tests/__init__.py

@@ -10,6 +10,10 @@ import os
 os.environ["VIRTINST_TEST_SUITE"] = "1"
 # Need to do this before we import argcomplete
 os.environ.pop("_ARC_DEBUG", None)
+# Make sure the test suite uses an English locale, as we need to match
+# error/status messages
+os.environ["LANG"] = "en_US.UTF-8"
+os.environ.pop("LANGUAGE", None)
 
 # pylint: disable=wrong-import-position
 from virtinst import buildconfig