Comment 4 for bug 1742971

We reproduced this some last week, and I noticed that we're getting 404's when the failing node tries to retrieve its preseed:

10.244.40.31/var/log/maas/regiond.log:2018-03-15 11:28:33 regiond: [info] 10.244.40.32 GET /metadata/latest/by-id/cwerrd/?op=get_preseed HTTP/1.1 --> 404 NOT_FOUND (referrer: -; agent: Cloud-Init/17.2)

The problem there is the /MAAS prefix is missing from the path; here's a successful request from another VM:
10.244.40.32/var/log/maas/regiond.log:2018-03-15 11:29:04 regiond: [info] 10.244.40.32 GET /MAAS/metadata/latest/by-id/w3hg84/?op=get_preseed HTTP/1.1 --> 200 OK (referrer: -; agent: Cloud-Init/17.2)

notice the /MAAS in the URL on the successful one.

Now, the question is why the /MAAS is missing in the failure case.