Fix tox4 error

tox.ini started failing with Tox4 which had some
incompatible changes. One of them is due to the
skipsdist = True.

Fixing tox.ini for tox4 changes.

Additional changes:
* zuul: Declare queue at top level
* fix onflicting with base python error

Change-Id: I9f988e485c1c19eca41175e29fc09c1e28d38b06
(cherry picked from commit deaf2f4f81)
(cherry picked from commit 2719d659d9)

.zuul.yaml

@@ -1,4 +1,5 @@
 - project:
+    queue: kuryr
     templates:
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
@@ -6,5 +7,4 @@
       - release-notes-jobs-python3
       - publish-openstack-docs-pti
       - check-requirements
-    gate:
-      queue: kuryr
+    gate: {}

tox.ini

@@ -1,10 +1,8 @@
 [tox]
 minversion = 2.3.1
 envlist = py37,pep8
-skipsdist = True
 
 [testenv]
-basepython = python3
 # Note the hash seed is set to 0 until neutron can be tested with a
 # random hash seed successfully.
 setenv = VIRTUAL_ENV={envdir}