account-widget: don't display "Log in" button if we are modyfing an account
account-widget: don't display "Log in" button if we are modyfing an account

Either the account is enabled and saving will reconnect, either it's not and
that won't connect it.

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