Correction of a bug on the writting part for the configuration by properties.

src/main/java/fr/soleil/opcuaproxy/attributes/OpcUaAttributeParser.java

@@ -111,7 +111,7 @@ public class OpcUaAttributeParser {
 				if (nbWriteParts > 0) {
 					writeParts = new ArrayList<>(nbWriteParts);
 					for (int i = 0; i < nbWriteParts; i++) {
-						String writePart = elems[i + 2].trim();
+						String writePart = elems[OPCUA_WRITE_IDX+i].trim();
 						OpcUaSimpleNode writeNode = null;
 						if (writePart.length() > 0) {
 							writeNode = splitNamespaceTypeId(writePart);