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/stream.go b/vendor/google.golang.org/grpc/stream.go
index bb99940..934ef68 100644
--- a/vendor/google.golang.org/grpc/stream.go
+++ b/vendor/google.golang.org/grpc/stream.go
@@ -31,7 +31,6 @@
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/encoding"
-	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/internal/balancerload"
 	"google.golang.org/grpc/internal/binarylog"
 	"google.golang.org/grpc/internal/channelz"
@@ -498,13 +497,13 @@
 		if len(sps) == 1 {
 			var e error
 			if pushback, e = strconv.Atoi(sps[0]); e != nil || pushback < 0 {
-				grpclog.Infof("Server retry pushback specified to abort (%q).", sps[0])
+				channelz.Infof(cs.cc.channelzID, "Server retry pushback specified to abort (%q).", sps[0])
 				cs.retryThrottler.throttle() // This counts as a failure for throttling.
 				return err
 			}
 			hasPushback = true
 		} else if len(sps) > 1 {
-			grpclog.Warningf("Server retry pushback specified multiple values (%q); not retrying.", sps)
+			channelz.Warningf(cs.cc.channelzID, "Server retry pushback specified multiple values (%q); not retrying.", sps)
 			cs.retryThrottler.throttle() // This counts as a failure for throttling.
 			return err
 		}