Reduce redundante call to bytes.ToLower and substitute the last call by an home made version doing the conversion in place

Former-commit-id: d9ea22f649d97be352f8dbb37acc1495df830118

pkg/obiutils/bytes.go

@@ -0,0 +1,11 @@
+package obiutils
+
+func InPlaceToLower(data []byte) []byte {
+	for i,l := range data {
+		if l >= 'A' && l <='Z' {
+			data[i]|=32
+		}
+	}
+
+	return data
+}