So far as search goes, there should be NO difference between HTTP or HTTPS -- the ONLY thing I can think of that would make a difference is that HTTPS is slower -- and Google HAS been penalizing slow loading websites... but that's why Google introduced SPDY so you can have HTTPS and have it even run faster than normal HTTP... in theory... in practice the server-side overhead can piss all over that resulting in it being more of a wash apart from the open connection reducing the multi-file request overhead. If you've got an inefficient file count, SPDY can pay off... if you don't, it's a wash.
But in terms of impact on search JUST because it's HTTPS instead of HTTP? BULL! 100% grade A farm fresh fiction -- I'd be interested in seeing an actual link to an ACTUAL Google employee saying ANYTHING along these lines, as I'm unable to find any such reference clearly lumping this into the same hoodoo-voodoo witch doctor fiction as the rest of the SEO Scam Artist nonsense. Just another thing to make a wild claim about to trick the ignorant, that isn't based in anything remotely resembling fact. You can find plenty of "i speeda de engrish" SEO-tard's CLAIMING Google said it, but... where's the link to where it's actually SAID?!?
In other words, business as usual for the people more interested in gaming the system to polish that turd than they are in generating content of value and genuine interest on the part of visitors.