fix(e2e): prevent chrome race condition (angular#1141)

This should help with flakyness on chrome tests, especially e2e.

For more information see:
- angular/protractor#2419 (comment)
- angular/protractor#2419 (comment)

Author: filipesilva

.travis.yml

@@ -1,8 +1,11 @@
 dist: trusty
 sudo: required
 env:
-  - NODE_VERSION=5 SCRIPT=lint
-  - NODE_VERSION=5 SCRIPT=test
+  global:
+    - DBUS_SESSION_BUS_ADDRESS=/dev/null
+  matrix:
+    - NODE_VERSION=5 SCRIPT=lint
+    - NODE_VERSION=5 SCRIPT=test
 os:
   - linux
   - osx