Fix GCS backend from https://github.com/mozilla/sccache/pull/212
Fix GCS backend from https://github.com/mozilla/sccache/pull/212

luser/sccache2,glandium/sccache,luser/sccache2,mozilla/sccache,luser/sccache2,glandium/sccache,mozilla/sccache,luser/sccache2,glandium/sccache,mozilla/sccache,glandium/sccache