Handle auth token when cancelling the login

[fjaguero]

After cancelling the authentication, twitter throws the following error: "It looks like that already used the token information you provided".

Steps to reproduce:

• Launch the app
• Click on "Conectarme"
• Cancel authentication
• Click on "Conectarme"

Launched in Firefox OS 1.4 simulator.

[willyaranda]

Mmm… this might be related with SSL connection cache on my nginx deployment, or even spdy, that reuses the connection so express thinks (correctly) that it's the same user and does not create new tokens to connect to twitter.

[fjaguero]

I will try to reproduce it in my environment