title: Laravel MIME validation - disallowed extension goes through when file is not empty
body: <p>I'm using Laravel 5.2. For one of my forms I have these validation rules for a file:</p>
  
  <pre><code>$rules = array('file' =&gt; 'required|mimes:pdf,jpg,png,docx');
  </code></pre>
  
  <p>So a simple whitelist of extensions. Then, I validate the field as follows:</p>
  
  <pre><code>$validator = Validator::make(Input::all(), $rules);
  
  if ($validator-&gt;fails()) {
      // redirect with errors
  }
  </code></pre>
  
  <p>Now, I'm trying to test it, so I upload a file from out of the whitelist - an <em>empty</em> JS file (test.js) - and the validation fails, which is OK. But <em>as soon as I put some content in the same JS file</em>, the upload goes through, even if the file MIME type is the same ("application/javascript").</p>
  
  <p>Tried it with an SQL file (test.sql) - the same. Validation works properly only for the empty file.</p>
  
  <p>What might be the problem?</p>