Previously, the ac2dm was meant to be saved in the application state, and later used for
subsequent logins, along with the gsfId. This is not correct, because the app needs it
only for the first login, and then remains unused in the application state.
The correct behaviour is to save the gsfId and the authSubToken, and provide only these two
values for subsequent logins
Signed-off-by: Domenico Iezzi <domenico.iezzi.201@gmail.com>