Fix selection when adding to s2-options

[Jasu]

When a new item is added to s2-options, the option can be selected in the menu, but after that ng-model is set to null, since optionItems has not been refreshed. This patch adds refreshing of optionItems into opts.query for the normal case too.

[marioBonales]

I just stumbled with this bug, your solution works perfectly, thanks a lot! You saved me a bunch of debugging time trying to figure this out