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/google.golang.org/grpc/balancer/balancer.go b/vendor/google.golang.org/grpc/balancer/balancer.go
index 317c2e7..67518de 100644
--- a/vendor/google.golang.org/grpc/balancer/balancer.go
+++ b/vendor/google.golang.org/grpc/balancer/balancer.go
@@ -61,7 +61,7 @@
 }
 
 // Get returns the resolver builder registered with the given name.
-// Note that the compare is done in a case-insenstive fashion.
+// Note that the compare is done in a case-insensitive fashion.
 // If no builder is register with the name, nil will be returned.
 func Get(name string) Builder {
 	if b, ok := m[strings.ToLower(name)]; ok {
@@ -127,7 +127,7 @@
 	// The SubConn will be shutdown.
 	RemoveSubConn(SubConn)
 
-	// UpdateBalancerState is called by balancer to nofity gRPC that some internal
+	// UpdateBalancerState is called by balancer to notify gRPC that some internal
 	// state in balancer has changed.
 	//
 	// gRPC will update the connectivity state of the ClientConn, and will call pick
@@ -227,9 +227,10 @@
 	// - Else (error is other non-nil error):
 	//   - The RPC will fail with unavailable error.
 	//
-	// The returned done() function will be called once the rpc has finished, with the
-	// final status of that RPC.
-	// done may be nil if balancer doesn't care about the RPC status.
+	// The returned done() function will be called once the rpc has finished,
+	// with the final status of that RPC.  If the SubConn returned is not a
+	// valid SubConn type, done may not be called.  done may be nil if balancer
+	// doesn't care about the RPC status.
 	Pick(ctx context.Context, opts PickOptions) (conn SubConn, done func(DoneInfo), err error)
 }