iOS 7 is focusing hidden search field and pulling out keyboard

I've noticed this problem on an iPad running iOS 7:

select2 is initialized with `minimumResultsForSearch: -1` and search field is hidden as it should be, but it actually gets focused and keyboard is pulled out, which is pretty annoying.

The fix is simply making sure that `showSearchInput` is enabled before focusing search field or making any other changes to it.