App sidebar: fix icon label

Before : https://drive.google.com/file/d/0B6HSD0BaBeKoNnVPUGFhZmVqVUE/edit?usp=sharing
After : https://drive.google.com/file/d/0B6HSD0BaBeKoUDJrTGUtNFRuMzQ/edit?usp=sharing

don't cherry-pick this if you don't have any problem.

Change-Id: Iafcfad21c1c4345986f9648c3909296b842a3768