So far, the devstack-tobiko-octavia upstream job didn't vote either as a
check or a gate pipline.
We made it a non voting u/s job back then because it wasn't stable some
time ago.
As today that upstream job is stable enough to be voting again, this
patch makes it voting.
Change-Id: Icd62c191f0cacefd66c0a546587529062583790c