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/internal/channelz/funcs.go b/vendor/google.golang.org/grpc/internal/channelz/funcs.go
index f0744f9..e4252e5 100644
--- a/vendor/google.golang.org/grpc/internal/channelz/funcs.go
+++ b/vendor/google.golang.org/grpc/internal/channelz/funcs.go
@@ -30,7 +30,7 @@
 	"sync/atomic"
 	"time"
 
-	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/grpclog"
 )
 
 const (
@@ -216,7 +216,7 @@
 // by pid). It returns the unique channelz tracking id assigned to this subchannel.
 func RegisterSubChannel(c Channel, pid int64, ref string) int64 {
 	if pid == 0 {
-		grpclog.Error("a SubChannel's parent id cannot be 0")
+		grpclog.ErrorDepth(0, "a SubChannel's parent id cannot be 0")
 		return 0
 	}
 	id := idGen.genID()
@@ -253,7 +253,7 @@
 // this listen socket.
 func RegisterListenSocket(s Socket, pid int64, ref string) int64 {
 	if pid == 0 {
-		grpclog.Error("a ListenSocket's parent id cannot be 0")
+		grpclog.ErrorDepth(0, "a ListenSocket's parent id cannot be 0")
 		return 0
 	}
 	id := idGen.genID()
@@ -268,7 +268,7 @@
 // this normal socket.
 func RegisterNormalSocket(s Socket, pid int64, ref string) int64 {
 	if pid == 0 {
-		grpclog.Error("a NormalSocket's parent id cannot be 0")
+		grpclog.ErrorDepth(0, "a NormalSocket's parent id cannot be 0")
 		return 0
 	}
 	id := idGen.genID()
@@ -294,7 +294,19 @@
 }
 
 // AddTraceEvent adds trace related to the entity with specified id, using the provided TraceEventDesc.
-func AddTraceEvent(id int64, desc *TraceEventDesc) {
+func AddTraceEvent(id int64, depth int, desc *TraceEventDesc) {
+	for d := desc; d != nil; d = d.Parent {
+		switch d.Severity {
+		case CtUNKNOWN:
+			grpclog.InfoDepth(depth+1, d.Desc)
+		case CtINFO:
+			grpclog.InfoDepth(depth+1, d.Desc)
+		case CtWarning:
+			grpclog.WarningDepth(depth+1, d.Desc)
+		case CtError:
+			grpclog.ErrorDepth(depth+1, d.Desc)
+		}
+	}
 	if getMaxTraceEntry() == 0 {
 		return
 	}