In notifyWelcomeFacebookUser, we include an LBB user/pass for the user
should they want to login to LBB but not through FB.

Previously, if you created your account by logging in via FB, you got a
welcome email saying as much.  But there was no mention of your LBB
user/pass.  So if you created your account via FB login, there was no
way to login via LBB.