title: WTForms field defaults suddenly don't work
body: <p>I have the following code:</p>
  
  <pre><code>class ReconForm(Form):
      compressedFilePath = StringField('Compressed File Path', [validators.Required()] )
  </code></pre>
  
  <p>and I instantiate it like this:</p>
  
  <pre><code>form = ReconForm()
  form.compressedFilePath.default = 'hey'
  </code></pre>
  
  <p>It does nothing. It used to set the default value to hey but then it stopped and I have no idea why.</p>
  
  <p>If I print form.compressedFilePath.default then it prints the correct value. If I set a default in the field constructor the template renders the correct value. Otherwise it just does nothing and it's driving me crazy.</p>
  
  <p>What am I doing wrong?</p>