(#2781) - rollback to websql on safari/ios 8

Yeah, I know: I'm finally resorting to browser-sniffing. Even though we have [a working reproducible test](http://bl.ocks.org/nolanlawson/c83e9039edf2278047e9).

But listen, I just do not have the time to rearchitect our entire adapter validation logic to make it asynchronous so we can detect a dumb bug that hopefully the WebKit devs will fix soon anyway.

Submitting this as-is. Saucelabs doesn't support Safari 7.1 or iOS 8 yet, so you'll have to take my word for it that it passes.

I look forward to when we can revert this commit.