As of Stein, nova adds a 'COMPUTE_NET_ATTACH_INTERFACE' trait to ironic
resource providers in placement. This means that they no longer match our
expected set of traits.
This patch removes this trait from the list of expected traits.
Change-Id: I84bf367d31b10144617c0d66cc21dbcb5b0908a8
Story: 2005309
Task: 30210