httpreplay: fix test for kokoro
httpreplay: fix test for kokoro

In TestRemoveAndClear, create the client without auth to avoid
an oauth2 token-refresh error when running on kokoro.

Change-Id: Ibb86ec9cea5bcfb342cf63939ea4d2abad21d26f
Reviewed-on: https://code-review.googlesource.com/c/37430
Reviewed-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Jean de Klerk <605b93664484fed1e671a07bff68da39e73d0174@google.com>

googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go