Previously these were all hardcoded; let operators tweak them as needed.
Significantly, this also allows operators to disable error-limiting
entirely, which may be a useful protection in case proxies are
configured with a single memcached server.
Use error_suppression_limit and error_suppression_interval to mirror the
option names used by the proxy-server to ratelimit backend Swift
servers.
Co-Authored-By: Alistair Coles <alistairncoles@gmail.com>
Change-Id: Ife005cb8545dd966d7b0e34e5496a0354c003881
aff65242ff