Fix suggestions keyup timeout.

The browser was generating one AJAX request per keystroke, ignoring the
timeout. The clearTimeout() function needs to be called with the ID
value returned by setTimeout().

app/assets/javascripts/suggest.js.coffee

@@ -16,8 +16,10 @@ App.Suggest =
             js_suggest_selector = $this.data('js-suggest')
             $(js_suggest_selector).html(stHtml)
 
+      timer = null
+
       $this.on 'keyup', ->
-        window.clearTimeout(callback)
-        window.setTimeout(callback, 1000)
+        window.clearTimeout(timer)
+        timer = window.setTimeout(callback, 1000)
 
       $this.on 'change', callback