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/grpclog/logger.go b/vendor/google.golang.org/grpc/grpclog/logger.go
index 097494f..ef06a48 100644
--- a/vendor/google.golang.org/grpc/grpclog/logger.go
+++ b/vendor/google.golang.org/grpc/grpclog/logger.go
@@ -18,6 +18,8 @@
 
 package grpclog
 
+import "google.golang.org/grpc/internal/grpclog"
+
 // Logger mimics golang's standard Logger as an interface.
 //
 // Deprecated: use LoggerV2.
@@ -35,7 +37,7 @@
 //
 // Deprecated: use SetLoggerV2.
 func SetLogger(l Logger) {
-	logger = &loggerWrapper{Logger: l}
+	grpclog.Logger = &loggerWrapper{Logger: l}
 }
 
 // loggerWrapper wraps Logger into a LoggerV2.