Fix French translation.

When you ask to authenticate a contact in the French release of Jitsi, the question/answer translation is false and you have two text-boxes named "réponse".

![jitsi_before](https://cloud.githubusercontent.com/assets/1536039/4497299/b26dc7a2-4a6d-11e4-800a-0c22f94078f4.png)

This patch fixes the translation and the first text field is now "Votre question :".