title: Vim: Airline + Syntastic bug
body: <p>I am unable to get Airline to work properly with syntastic. I have a clean installation of Python (3.5.3), Vim (where there are only Syntastic and Airline installed via Vundle) and Flake8.</p>
  
  <p>When I open python code in Vim I get this message:</p>
  
  <pre class="lang-none prettyprint-override"><code>Error detected while processing function
  &lt;SNR&gt;20_on_window_changed[13]..airline#update_statusline[18]..
  &lt;SNR&gt;21_invoke_funcrefs[2]..airline#util#exec_funcrefs[2]..
  airline#extensions#quickfix#apply[2]..&lt;SNR&gt;40_get_text:
  line    3:
  E716: Key not present in Dictionary: quickfix &amp;&amp; !dict[0].loclist
  Press ENTER or type command to continue
  Error detected while processing function    
  &lt;SNR&gt;20_on_window_changed[13]..airline#update_statusline[18].
  &lt;SNR&gt;21_invoke_funcrefs[2]..airline#util#exec_funcrefs[2]..
  airline#extensions#quickfix#apply[2]..&lt;SNR&gt;40_get_text:
  line    3:
  E15: Invalid expression: len(dict) &gt; 0 &amp;&amp; dict[0].quickfix &amp;&amp; 
  !dict[0].loclist
  </code></pre>
  
  <p>What could this possibly mean?</p>
  
  <p>Here's what my vimrc looks like:</p>
  
  <pre><code>set nocompatible              " be iMproved, required
  filetype off                  " required
  
  "=====================================================
  " Vundle settings
  "=====================================================
  " set the runtime path to include Vundle and initialize
  
  set rtp+=C:/Users/Ray/.vim/bundle/Vundle.vim/
  call vundle#begin()
  
  Plugin 'VundleVim/Vundle.vim'
  Plugin 'vim-syntastic/syntastic'
  Plugin 'vim-airline/vim-airline'
  Plugin 'vim-airline/vim-airline-themes'
  
  
  " All of your Plugins must be added before the following line
  call vundle#end()            " required
  filetype on
  filetype plugin on
  filetype plugin indent on
  
  
  "let g:airline#extensions#tabline#enabled = 1
  set laststatus=2
  "let g:airline_powerline_fonts = 1
  
  set statusline+=%#warningmsg#
  set statusline+=%{SyntasticStatuslineFlag()}
  set statusline+=%*
  
  let g:syntastic_always_populate_loc_list = 1
  let g:syntastic_auto_loc_list = 1
  let g:syntastic_check_on_open = 1
  let g:syntastic_check_on_wq = 0
  </code></pre>