fix(Xapi#createBondedNetwork): mac param should be a string (#588)

src/api/network.js

@@ -54,6 +54,7 @@ createBonded.params = {
     }
   },
   mtu: { type: ['integer', 'string'], optional: true },
+  mac: { type: 'string', optional: true },
   // RegExp since schema-inspector does not provide a param check based on an enumeration
   bondMode: { type: 'string', pattern: new RegExp(`^(${getBondModes().join('|')})$`) }
 }

src/xapi/index.js

@@ -1999,7 +1999,7 @@ export default class Xapi extends XapiBase {
   @deferrable.onFailure
   async createBondedNetwork ($onFailure, {
     bondMode,
-    mac,
+    mac = '',
     pifIds,
     ...params
   }) {