Detect when there is a change bewwen a https connection to a non-secure one and generated a new erro code.
Fixed bug. It is not possible to connect to a http server
Fixed check of HTTPS downgrade so that works with multiple redirections, and done without an extra request
Fixed logic of HTTPS downgrade detection for multiple redirections, and grant that redirection if followed for HTTP servers
Merge pull request #35 from owncloud/unsecured_server_connection

Unsecured server connection