Fixing version in book.json file

Change-Id: I81927a54e9627148df9d58dda7a48e76590cd420
diff --git a/docs/book.json b/docs/book.json
index 4f49240..84d44f7 100644
--- a/docs/book.json
+++ b/docs/book.json
@@ -13,7 +13,6 @@
   ],
   "pluginsConfig": {
     "versions": {
-      "gitbookConfigURL": "https://raw.githubusercontent.com/opencord/cord/master/docs/book.json",
       "options": [
         {
           "value": "http://guide.opencord.org/cord-4.0",