Add HTTPSeeOther(303) and HTTPTemporaryRedirect(307) to swob

RFC 1945 and RFC 2068 specify that the client is not allowed to change the
method on the redirected request.  However, most existing user agent
implementations treat 302 as if it were a 303 response, performing a GET on
the Location field-value regardless of the original request method. The status
codes 303 and 307 have been added for servers that wish to make unambiguously
clear which kind of reaction is expected of the client.

HTTP/1.1 RFC for 302: http://tools.ietf.org/html/rfc2616#section-10.3.4
HTTP/1.1 RFC for 307: http://tools.ietf.org/html/rfc2616#section-10.3.8

Change-Id: I354e2f4f3e3eb6a1553b3d9c60b613d8f0c37531
Signed-off-by: Prashanth Pai <ppai@redhat.com>
Merge "Add HTTPSeeOther(303) and HTTPTemporaryRedirect(307) to swob"