Switch "useGranter" to "granter"

MultiPart: 2/2
Change-Id: I3402ab9b687dd802f611cdcac87523770bb1039a
diff --git a/services/wspr/internal/app/app.go b/services/wspr/internal/app/app.go
index 1496e41..def232b 100644
--- a/services/wspr/internal/app/app.go
+++ b/services/wspr/internal/app/app.go
@@ -225,7 +225,7 @@
 			callOpts = append(callOpts, options.AllowedServersPolicy(v.Value))
 		case RpcCallOptionRetryTimeout:
 			callOpts = append(callOpts, options.RetryTimeout(v.Value))
-		case RpcCallOptionUseGranter:
+		case RpcCallOptionGranter:
 			callOpts = append(callOpts, &jsGranter{c, v.Value})
 		default:
 			return nil, fmt.Errorf("Unknown RpcCallOption type %T", v)