Fix default case causing the throttling to not be used. Ensure that nil client condition is handled. Signed-off-by: Derek McGowan <derek@mcgstyle.net> (cherry picked from commit c3e32938430e03a316311f9e4fbdb743e492a07e) Signed-off-by: Andrew Hsu <andrewhsu@docker.com> Upstream-commit: f121eccf29576ce5d4b8256a71a9d32ee688ff7d Component: engine