VOL-1460 Updated core to use voltha-protos instead of local protos
Moved protos to python directory in order to maintain functionaly of containers built there.
Added capability to do local builds of protos
Added instructions on running dep ensure for getting protos.
Updated github.com/golang/protobuf version to v1.3.1

Change-Id: Ia6ef55f07f0d5dcb5b750d7c37b21b71db85bfc4
diff --git a/vendor/github.com/golang/protobuf/proto/properties.go b/vendor/github.com/golang/protobuf/proto/properties.go
index 50b99b8..79668ff 100644
--- a/vendor/github.com/golang/protobuf/proto/properties.go
+++ b/vendor/github.com/golang/protobuf/proto/properties.go
@@ -334,9 +334,6 @@
 	sprop, ok := propertiesMap[t]
 	propertiesMu.RUnlock()
 	if ok {
-		if collectStats {
-			stats.Chit++
-		}
 		return sprop
 	}
 
@@ -346,17 +343,20 @@
 	return sprop
 }
 
+type (
+	oneofFuncsIface interface {
+		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
+	}
+	oneofWrappersIface interface {
+		XXX_OneofWrappers() []interface{}
+	}
+)
+
 // getPropertiesLocked requires that propertiesMu is held.
 func getPropertiesLocked(t reflect.Type) *StructProperties {
 	if prop, ok := propertiesMap[t]; ok {
-		if collectStats {
-			stats.Chit++
-		}
 		return prop
 	}
-	if collectStats {
-		stats.Cmiss++
-	}
 
 	prop := new(StructProperties)
 	// in case of recursive protos, fill this in now.
@@ -391,13 +391,14 @@
 	// Re-order prop.order.
 	sort.Sort(prop)
 
-	type oneofMessage interface {
-		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
+	var oots []interface{}
+	switch m := reflect.Zero(reflect.PtrTo(t)).Interface().(type) {
+	case oneofFuncsIface:
+		_, _, _, oots = m.XXX_OneofFuncs()
+	case oneofWrappersIface:
+		oots = m.XXX_OneofWrappers()
 	}
-	if om, ok := reflect.Zero(reflect.PtrTo(t)).Interface().(oneofMessage); ok {
-		var oots []interface{}
-		_, _, _, oots = om.XXX_OneofFuncs()
-
+	if len(oots) > 0 {
 		// Interpret oneof metadata.
 		prop.OneofTypes = make(map[string]*OneofProperties)
 		for _, oot := range oots {