Fix tox coverange env

We're not setting the VIRTUAL_ENV environment variable, so 'tox -ecover'
is failing because patch_tox_venv uses the variable.

Change-Id: I3898d0dd1f8a9bf4216253bb2c7d8491e1e8ce56

1 files changed, 2 insertions, 1 deletions

diff --git a/tox.ini b/tox.ini
index c23df7f..cf32dad 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,7 +29,8 @@ commands = python ./tools/lint.py ./openstack
            python ./tools/lint.py ./tests
 
 [testenv:cover]
-setenv = NOSE_WITH_COVERAGE=1
+setenv = VIRTUAL_ENV={envdir}
+         NOSE_WITH_COVERAGE=1
 
 [testenv:venv]
 commands = {posargs}