md-autocomplete: hasNotFoundTemplate isn't evaulated accurately

[clshortfuse]

If you have multiple md-autocomplete items, hasNotFoundTemplate is sometimes incorrect. I'm not 100% how, but through stepping

var hasNotFoundTemplate = false;

is only executed once and it's a global variable that would affect all md-autocomplete values.

Here's a (sloppy) codepen to show the issue: http://codepen.io/anon/pen/PPemGr

If you type in the second box (without a md-not-found tag) and with no results found, ctrl.hasNotFound will be true. This means the box will show because notFoundVisible() will equate to true, making shouldShow() true.

Thought my stepping, it seems as though every item will iterate through the the template function, then every element will through the link command.

Also, hasNotFoundTemplate is never evaluated back to false.