Rename tox_venvlist (2/2)

For consistency with the tox jobs, use tox_envlist instead of
tox_venvlist.

We need first to add a new parameter, then change the job, then
remove the old parameter.

Depends-On: I67a20b1faa77ff0166ad96fd95432c11948abc74
Change-Id: If76fb60f1d750a063c994bd596d6f93f25b3a854
diff --git a/.zuul.yaml b/.zuul.yaml
index a281acc..07bce4e 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -79,7 +79,6 @@
         neutron-dns: True
         tempest: True
       tempest_test_regex: '^neutron_tempest_plugin\.scenario\.test_dns_integration'
-      tox_venvlist: all-plugin
       tox_envlist: all-plugin
     irrelevant-files:
       - ^(test-|)requirements.txt$