Enable parallelism on DVR job

As the neutron full job is now voting, it makes sense to enable
parallel testing also on this experimental job.
This might allow to uncover race conditions which went unnoticed
so far.

It looks like there is no reason for running the full test suite
for the DVR job.

Change-Id: Ic066fd43ff2509d08c97d867bc03f485b95f3b74
Merge "Enable parallelism on DVR job"