0043479: It is possible to generate a cache for mobile applications with no service workers

# HG changeset patch
# User Ranjith S R <ranjith@qualiantech.com>
# Date 1585727398 -19800
#      Wed Apr 01 13:19:58 2020 +0530
# Node ID ccb0b9e095fa4fb07f606d08278be9aea0036687
# Parent  92d70d9dfefb5c6a8a041d5f0511cc32f482be5c
Fixed issue-43479 : Added ServiceWorker validation while fetching resources

* Cache should not be generated if ServiceWorker is not available

diff -r 92d70d9dfefb -r ccb0b9e095fa web/org.openbravo.mobile.core/source/offline/ob-fetch-manifest.js
--- a/web/org.openbravo.mobile.core/source/offline/ob-fetch-manifest.js	Thu Mar 26 22:34:40 2020 -0400
+++ b/web/org.openbravo.mobile.core/source/offline/ob-fetch-manifest.js	Wed Apr 01 13:19:58 2020 +0530
@@ -7,14 +7,17 @@
  ************************************************************************************
  */
 
-/*global fetch*/
+/*global fetch, ServiceWorkerUtil */
 
 OB.UTIL.fetchApplicationSources = function(
   successNoRefreshCallback,
   errorCallback
 ) {
   //make sure that Service Workers are supported.
-
+  if (typeof ServiceWorkerUtil === 'undefined') {
+    successNoRefreshCallback();
+    return;
+  }
   var setManifest = false,
     manifest,
     manifestType,