add new fieds for ICE and DTLS (#538)

lib/models/sip-gateway.js

@@ -66,6 +66,14 @@ SipGateway.fields = [
   {
     name: 'protocol',
     type: 'string'
+  },
+  {
+    name: 'remove_ice',
+    type: 'number'
+  },
+  {
+    name: 'dtls_off',
+    type: 'number'
   }
 ];