title: rstudio push 'rpostback-askpass' error
body: <p>From CLI, I can push/pull to git. However, from Rsudio, I'm only able to pull but not to push. I have opened my firewall for ssh/https ports 
  but I'm still getting the following error when trying to push:</p>
  
  <pre><code>error: unable to read askpass response from 'rpostback-askpass'
  fatal: could not read Username for 'https://github.com': No such device or address
  </code></pre>
  
  <p>Rstudio Version 0.99.484.</p>