veyron/wspr/services/wsprd/browspr/main/main_nacl.go: TBR Fix the build.

Change-Id: I4c491393bc068bc9a98cdc7a6d3f61c726725847
diff --git a/services/wsprd/browspr/main/main_nacl.go b/services/wsprd/browspr/main/main_nacl.go
index 2c688bf..97473f7 100644
--- a/services/wsprd/browspr/main/main_nacl.go
+++ b/services/wsprd/browspr/main/main_nacl.go
@@ -58,7 +58,7 @@
 		return fmt.Errorf("got key of type %T, want *ecdsa.PrivateKey", key)
 	}
 
-	principal, err := vsecurity.NewPrincipalFromSigner(security.NewInMemoryECDSASigner(ecdsaKey))
+	principal, err := vsecurity.NewPrincipalFromSigner(security.NewInMemoryECDSASigner(ecdsaKey), nil)
 	if err != nil {
 		return err
 	}