SEBA-902 single-olt tests;
Pin protoc-gen-go to 1.3.2 to resolve compatibility issue;
Run go mod tidy / go mod vendor on importer;
Add Go Module support to demotest

Change-Id: Ifde824fc9a6317b0adc1e12bea54ee1f9b788906
diff --git a/vendor/google.golang.org/grpc/rpc_util.go b/vendor/google.golang.org/grpc/rpc_util.go
index d3a4adc..cf9dbe7 100644
--- a/vendor/google.golang.org/grpc/rpc_util.go
+++ b/vendor/google.golang.org/grpc/rpc_util.go
@@ -287,13 +287,14 @@
 }
 func (o FailFastCallOption) after(c *callInfo) {}
 
-// MaxCallRecvMsgSize returns a CallOption which sets the maximum message size the client can receive.
-func MaxCallRecvMsgSize(s int) CallOption {
-	return MaxRecvMsgSizeCallOption{MaxRecvMsgSize: s}
+// MaxCallRecvMsgSize returns a CallOption which sets the maximum message size
+// in bytes the client can receive.
+func MaxCallRecvMsgSize(bytes int) CallOption {
+	return MaxRecvMsgSizeCallOption{MaxRecvMsgSize: bytes}
 }
 
 // MaxRecvMsgSizeCallOption is a CallOption that indicates the maximum message
-// size the client can receive.
+// size in bytes the client can receive.
 // This is an EXPERIMENTAL API.
 type MaxRecvMsgSizeCallOption struct {
 	MaxRecvMsgSize int
@@ -305,13 +306,14 @@
 }
 func (o MaxRecvMsgSizeCallOption) after(c *callInfo) {}
 
-// MaxCallSendMsgSize returns a CallOption which sets the maximum message size the client can send.
-func MaxCallSendMsgSize(s int) CallOption {
-	return MaxSendMsgSizeCallOption{MaxSendMsgSize: s}
+// MaxCallSendMsgSize returns a CallOption which sets the maximum message size
+// in bytes the client can send.
+func MaxCallSendMsgSize(bytes int) CallOption {
+	return MaxSendMsgSizeCallOption{MaxSendMsgSize: bytes}
 }
 
 // MaxSendMsgSizeCallOption is a CallOption that indicates the maximum message
-// size the client can send.
+// size in bytes the client can send.
 // This is an EXPERIMENTAL API.
 type MaxSendMsgSizeCallOption struct {
 	MaxSendMsgSize int