Revert "Skip unstable v6 scenario tests"

This reverts commit 461c83d287311447854016a286d1bbaf9f822769.

The neutron L3 team has been doing testing for the past few weeks
with this test re-enabled and does not see the failures
associated with it any more.

Change-Id: Ie30e5443447c76a6c6bc8afdf8150d23ddb6857e
1 file changed