Use OCSP live signing when not using Redis

patches/ocsp-responder_main.patch

@@ -1,5 +1,5 @@
 diff --git a/cmd/ocsp-responder/main.go b/cmd/ocsp-responder/main.go
-index 52027e8cd..320a41917 100644
+index 52027e8cd..4dcc9118a 100644
 --- a/cmd/ocsp-responder/main.go
 +++ b/cmd/ocsp-responder/main.go
 @@ -88,7 +88,7 @@ type Config struct {
@@ -20,3 +20,23 @@ index 52027e8cd..320a41917 100644
  		// Set up the redis source and the combined multiplex source.
  		rocspRWClient, err := rocsp_config.MakeClient(c.OCSPResponder.Redis, clk, scope)
  		cmd.FailOnError(err, "Could not make redis client")
+@@ -197,6 +197,19 @@ as generated by Boulder's ceremony command.
+ 
+ 		source, err = redis_responder.NewCheckedRedisSource(rocspSource, dbMap, sac, scope, logger)
+ 		cmd.FailOnError(err, "Could not create checkedRedis source")
++	} else {
++		tlsConfig, err := c.OCSPResponder.TLS.Load(scope)
++		cmd.FailOnError(err, "TLS config")
++
++		raConn, err := bgrpc.ClientSetup(c.OCSPResponder.RAService, tlsConfig, scope, clk)
++		cmd.FailOnError(err, "Failed to load credentials and create gRPC connection to RA")
++		rac := rapb.NewRegistrationAuthorityClient(raConn)
++
++		maxInflight := c.OCSPResponder.MaxInflightSignings
++		if maxInflight == 0 {
++			maxInflight = 1000
++		}
++		source = live.New(rac, int64(maxInflight), c.OCSPResponder.MaxSigningWaiters)
+ 	}
+ 
+ 	// Load the certificate from the file path.