Tiny fix for strict standards in Travis CI

System version 0.306
modules:
Blogs 0.050
Comments 0.012
Cron 0.006
Feedback 0.003
HybridAuth 2.1.1-cs24
OAuth2 0.016
Photo_gallery 0.002
Plupload 1.5.7-cs7
Static_pages 0.029
plugins:
Admin_default_theme 0.004
Fotorama 4.2.1-cs2
SimpleImage 2.3-cs1
TinyMCE 4.0.1-cs6