make swift-dsvm-functional job as voting
make swift-dsvm-functional job as voting

swift-dsvm-functional job test swift under python3 and
voting on swift gate whihc means this is a stable job now,
let's make this voting to devstack gate too.

Removing swift-dsvm-functional-py3 job as it does not exist anymore
after- https://review.opendev.org/c/openstack/swift/+/731318

swift-dsvm-functional itself is py3 job now.

Change-Id: I58847f74306194eaad132680815101a134fb4022

openstack-dev/devstack,openstack-dev/devstack,nawawi/openstack,nawawi/openstack