fixing tox requirements

Old link to download swift 1.9.1 is broken, updated to download directly

Change-Id: I02401c4f243376b58940b13e212d6dfafc1c76c9
Signed-off-by: Thiago da Silva <thiago@redhat.com>
Reviewed-on: http://review.gluster.org/6060
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>