update the travis config.

Author: Shouqun

.travis.yml

@@ -16,6 +16,7 @@ before_install:
   - sudo apt-get install -y dbus
   - sudo apt-get install -y libdbus-1-dev
   - sudo apt-get install -y libglib2.0-dev
+  - sudo apt-get install -y dbus-x11
 
 addons:
   apt: