Bug with dynamic binding multiple for select tag.

[34x]

Hello! First of all thank you for the great framework and your work.

I faced issue when tried to use select html tag with binded multiple attribute. But it does not work.
I have example on jsfiddle: https://jsfiddle.net/jqybwngo/

Partially copy bellow:

<div id="app">
  <select v-model="option" v-bind:multiple="isMultiple">
    <option value="1">item 1</option>
    <option value="2">item 2</option>
  </select>
</div>

And here is the error log from Safari (same for Firefox):

(found in root instance)
	warn (vue.js:525)
	setSelected (vue.js:5691)
	componentUpdated (vue.js:5672)
	callHook$1 (vue.js:4746)
	(anonymous function) (vue.js:4702)
	patchVnode (vue.js:4461)
	updateChildren (vue.js:4364)
	patchVnode (vue.js:4448)
	patch (vue.js:4572)
	_update (vue.js:2646)
	updateComponent (vue.js:2613)
	get (vue.js:2936)
	run (vue.js:3005)
	flushSchedulerQueue (vue.js:2811)
	(anonymous function) (vue.js:477)
	nextTickHandler (vue.js:426)
	promiseReactionJob
[Error] TypeError: binding.value.some is not a function. (In 'binding.value.some(function (v) { return hasNoMatchingOption(v, el.options); })', 'binding.value.some' is undefined)
componentUpdated — vue.js:5678
callHook$1 — vue.js:4746
https://unpkg.com/vue
patchVnode — vue.js:4461
updateChildren — vue.js:4364
patchVnode — vue.js:4448
patch — vue.js:4572
_update — vue.js:2646
updateComponent — vue.js:2613
get — vue.js:2936
run — vue.js:3005
flushSchedulerQueue — vue.js:2811
https://unpkg.com/vue
nextTickHandler — vue.js:426
promiseReactionJob

	logError (vue.js:439)
	promiseReactionJob

What is Expected?

Option is filled by array of selected values

What is actually happening?

Error reported in log, no parameter assigned.

[LinusBorg]

Note: The example works if mutliple is not bound with v-bind: https://jsfiddle.net/Linusborg/jqybwngo/2/