Only get client_access_key once
Only get client_access_key once

(cherry picked from commit 02b5308a64c88583cf280f9d591a82bef6625f69)

uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend