Tolerate 404s during setUp/tearDown in func tests
Tolerate 404s during setUp/tearDown in func tests

A couple times, I've seen tests fail in the gate because we got back a
404 while trying to clean out the test account. The story that gets us
here seems to be:

 - One or more object servers take too long to respond to the initial
   DELETE request, so the test client gets back a 503 and sleeps so
   it can retry.
 - Meanwhile, the servers finish writing their tombstones and want to
   respond 204 (but probably *actually* respond 408 because the proxy
   killed the connection).
 - The test client sends its retry, and since the object servers now
   have tombstones, it gets back a 404.

But the thing is, this is *outside of the test scope* anyway, we're just
trying to get back to a sane state. If it's gone, s much the better!

For an example of this, see the failures on patchset 3 of
https://review.openstack.org/#/c/534978 (which both failed for the same
reason on different tests).

Change-Id: I9ab2fd430d4800f9f55275959a20e30f09d9e1a4

smerritt/swift,matthewoliver/swift,smerritt/swift,openstack/swift,smerritt/swift,swiftstack/swift,tipabu/swift,smerritt/swift,tipabu/swift,matthewoliver/swift,tipabu/swift,tipabu/swift,openstack/swift,openstack/swift,swiftstack/swift,matthewoliver/swift,openstack/swift,swiftstack/swift,matthewoliver/swift