Fix authentication to Drive

Steps to reproduce:
_(Using https://nightly-rainforest.nuxeo.com)_
On MacOS, using Safari.

HTTP

• Download Nuxeo Drive and add to applications.
• Open Nuxeo Drive.
• Go to Accounts tab and enter http://nightly-rainforest.nuxeo.com/nuxeo/.
• Click on Connect.
  => Login page opens.
• Enter credentials.
  (sometimes) => Login page goes blank, nothing happens. Account is not connected.
  (sometimes) => User is logged into Nuxeo and is on the Nuxeo dashboard page. Account is not connected.

HTTPS

• Download Nuxeo Drive and add to Applications.
• Open Nuxeo Drive.
• Go to Accounts tab and enter https://nightly-rainforest.nuxeo.com/nuxeo/.
• Click on Connect.
  => Error appears:
  Connection error: please check server URL