title: UICollectionView reloadData - EXC_BREAKPOINT
body: <p>I have a <code>UICollectionView</code> in the header of my <code>UITableView</code>. I remove the collectionView if there is no data. 
  I am getting EXC_BREAKPOINT crashes from line "<code>self.collectionView.reloadData()</code>"</p>
  
  <pre><code>var reccomend: [JSON]? = []
  
   func loadReccomend(){
              YazarAPI.sharedInstance.loadReccomendedArticles({ reccomend in
                  if let data = reccomend["articles"].arrayValue as [JSON]?{
                      self.reccomend = data
                      if (self.reccomend?.count)! &lt; 1 {
                          self.tableView.tableHeaderView = nil
                      }else{
                          self.collectionView.reloadData()
                      }
                  }
              })
          } 
  
      func numberOfSectionsInCollectionView(collectionView: UICollectionView) -&gt; Int {
                  return 1
              }
  
              func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -&gt; Int {
                  return self.reccomend?.count ?? 0
              }
  
              func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -&gt; UICollectionViewCell {
                  let cell = collectionView.dequeueReusableCellWithReuseIdentifier("ReccomendCell", forIndexPath: indexPath) as! ReccomendedCollectionViewCell
                  cell.article = self.reccomend?[indexPath.row]
                  return cell
              }
  </code></pre>
  
  <p>And result of <code>print(data)</code> :</p>
  
  <pre><code>[{
    "title" : "title0",
    "author_email" : null,
    "author_id" : 1884,
    "read_count" : 0,
    "is_favorite" : false,
  
  }, {
    "title" : "title1",
    "author_email" : null,
    "author_id" : 1884,
    "read_count" : 0,
    "is_favorite" : false,
  
  }]
  </code></pre>