Revert "Make tempest plugin sanity job non voting"

This reverts commit 9400fb6f7cc67bf129eebaf25efe129ce5bf9bbd.

Reason for revert: neutron-tempest-plugin is fixed now

Change-Id: Ibb2d7ca35165fc6ea38c278fb9faf54a4dcd4aff
diff --git a/zuul.d/project.yaml b/zuul.d/project.yaml
index 240af53..a7641a6 100644
--- a/zuul.d/project.yaml
+++ b/zuul.d/project.yaml
@@ -43,10 +43,7 @@
             irrelevant-files: *tempest-irrelevant-files
         - tempest-multinode-full-py3:
             irrelevant-files: *tempest-irrelevant-files
-        # TODO(gmann): make it non voting once failure is fixed in plugin
-        # https://zuul.opendev.org/t/openstack/build/2c2ed82bd12948b98d9ea7e2ebe625a8
         - tempest-tox-plugin-sanity-check:
-            voting: false
             irrelevant-files: &tempest-irrelevant-files-2
               - ^.*\.rst$
               - ^doc/.*$