Fix adding Bcc addresses from identity

Fixes that issue, but I kind of remember that there was a reason why the
updateHidden call was early in that code.

Lesson: Always comment your code, kids.

imp/js/autocomplete.js

@@ -175,9 +175,9 @@ var IMP_Autocompleter = Class.create({
     {
         this.data = [];
         this.currentEntries().invoke('remove');
-        this.updateHiddenInput();
         this.processValue($F(this.elt));
         this.processInput();
+        this.updateHiddenInput();
     },
 
     processInput: function()