[gold] Fix bug causing a 404 on /json/v2/expectations.
[gold] Fix bug causing a 404 on /json/v2/expectations.

Bug: skia:10522
Change-Id: I3eaa04e679f87af6da492ccd07b1d5948871a976
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/323679
Reviewed-by: Kevin Lubick <7cdab2cfab351f23814786ba39716e90eed69047@google.com>
Commit-Queue: Leandro Lovisolo <f558143c2568be8d55575d13f30a1fc5cb8009d5@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot