[VOL-2357]openolt adapter log_level command line argument should take log level names not int value

Change-Id: I63b94c5c546a11a6612f09fec6e0658633c96351
diff --git a/main.go b/main.go
index 9a3b97a..6b07362 100644
--- a/main.go
+++ b/main.go
@@ -444,8 +444,10 @@
 
 	// Setup logging
 
+	loglevel := log.StringToInt(cf.LogLevel)
+
 	// Setup default logger - applies for packages that do not have specific logger set
-	if _, err := log.SetDefaultLogger(log.JSON, cf.LogLevel, log.Fields{"instanceId": cf.InstanceID}); err != nil {
+	if _, err := log.SetDefaultLogger(log.JSON, loglevel, log.Fields{"instanceId": cf.InstanceID}); err != nil {
 		log.With(log.Fields{"error": err}).Fatal("Cannot setup logging")
 	}