Create the account even when user chooses to not create other one after
Create the account even when user chooses to not create other one after

As the account is not created in impl_signal_apply() any more, we have to be
smarter in impl_signal_prepare and call account_assistant_apply_account_and_finish in more cases.

That also means that account_assistant_account_enabled_cb doesn't have to
terminate the assistant if the salut account has not been created yet.

Fixes bug #609220.

GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets,GNOME/telepathy-account-widgets,GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets