Revert "Fix expected status code in Ironic lookup"

This reverts commit 7b8b06c71401b5ce13fc73ed13b0e49e648cba8b.

The wrong function was fixed - it was the heartbeat, not the lookup,
that was checking for the wrong status code.

Change-Id: I35f49ca4fa1295d266f68b72b6ecdd5184181bd5
Merge "Revert "Fix expected status code in Ironic lookup""