Fixing golang linters for VGC

Change-Id: I386d232c74ab47e24d92c18800dc144120b920da
diff --git a/internal/pkg/holder/holder.go b/internal/pkg/holder/holder.go
index 95c1483..4cf1838 100644
--- a/internal/pkg/holder/holder.go
+++ b/internal/pkg/holder/holder.go
@@ -26,8 +26,8 @@
 // point for a mutable value that represents a GRPC service interface to
 // VOLTHA
 type VolthaServiceClientHolder struct {
-	mutex           sync.RWMutex
 	volthaSvcClient voltha.VolthaServiceClient
+	mutex           sync.RWMutex
 }
 
 // VolthaServiceClientReference structure