integrate some std io error kinds with our status code abstraction

associate rocksdb error kinds with std io error kinds

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/error/mod.rs

@@ -178,6 +178,7 @@ impl Error {
 			| Self::FeatureDisabled(..) => response::bad_request_code(&self.kind()),
 			| Self::Reqwest(error) => error.status().unwrap_or(StatusCode::INTERNAL_SERVER_ERROR),
 			| Self::Conflict(_) => StatusCode::CONFLICT,
+			| Self::Io(error) => response::io_error_code(error.kind()),
 			| _ => StatusCode::INTERNAL_SERVER_ERROR,
 		}
 	}