[VOL-4290] Voltha go library updates for gRPC migration

Change-Id: I1aa2774beb6b7ed7419bc45aeb53fcae8a8ecda0
diff --git a/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go b/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go
index 53b2787..187c304 100644
--- a/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go
+++ b/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go
@@ -22,27 +22,20 @@
 // This package is EXPERIMENTAL.
 package serviceconfig
 
-import (
-	"google.golang.org/grpc/internal"
-)
-
 // Config represents an opaque data structure holding a service config.
 type Config interface {
-	isConfig()
+	isServiceConfig()
 }
 
 // LoadBalancingConfig represents an opaque data structure holding a load
-// balancer config.
+// balancing config.
 type LoadBalancingConfig interface {
 	isLoadBalancingConfig()
 }
 
-// Parse parses the JSON service config provided into an internal form or
-// returns an error if the config is invalid.
-func Parse(ServiceConfigJSON string) (Config, error) {
-	c, err := internal.ParseServiceConfig(ServiceConfigJSON)
-	if err != nil {
-		return nil, err
-	}
-	return c.(Config), err
+// ParseResult contains a service config or an error.  Exactly one must be
+// non-nil.
+type ParseResult struct {
+	Config Config
+	Err    error
 }