Previously, the replication_server setting could take one of three
states:
* If unspecified, the server would handle all available methods.
* If "true", "yes", "on", etc. it would only handle replication
methods (REPLICATE, SSYNC).
* If any other value (including blank), it would only handle
non-replication methods.
However, because SSYNC tunnels PUTs, POSTs, and DELETEs through
the same object-server app that's responding to SSYNC, setting
`replication_server = true` would break the protocol. This has
been the case ever since ssync was introduced.
Now, get rid of that second state -- operators can still set
`replication_server = false` as a principle-of-least-privilege guard
to ensure proxy-servers can't make replication requests, but replication
servers will be able to serve all traffic. This will allow replication
servers to be used as general internal-to-the-cluster endpoints, leaving
non-replication servers to handle client-driven traffic.
Closes-Bug: #1446873
Change-Id: Ica2b41a52d11cb10c94fa8ad780a201318c4fc87
9eb81f6e69