bumping django_openstack_auth version

Dependency for fixing Horizon bug.

Change-Id: Ie8202544fbc227e1b86e18525c19096c498a64b4
Partial-Bug: #1211535
Set python-six minimum version

missing python-six minimum version from the requirements.txt
set the min version to 1.4.1

fixes bug: #1237205

Change-Id: I74b3324aa09412b49ce8eeaba9910ee6852e520a