The FAQ states that you get nothing from the "+1 to existing divine spellcaster class" that isn't listed in the original class's Spell section. http://paizo.com/paizo/faq/v5748nruor1fm#v5748eaic9rae
Some people argue that domain is an ability that is fully granted at cleric's first level and while you wouldn't gain any more domain powers you would still gain the domain spells. I argue it works like sorcerer's bloodlines and you don't get the spells if you don't put in the levels into the base class. The ambiguity arises because the FAQ doesn't specifically list cleric (though it does contain an et cetera). It also feels unfair that only clerics get their extra spells once they leave their class.
My friend is planning on playing a Holy Vindicator and we've been arguing back and forth about this for a few days. I was hoping to get a definitive answer before we brought it up to our GM, so if this has been answered in the past I would appreciate a link. If not, I'd love for a design team member to weigh in on this and why.