Setting a cookie with the same name as a previously deleted cookie
would set its expiry date to 'Thu, 01-Jan-1970 00:00:00 GMT'.

Thanks gjanee@ucop.edu for the report and Tim Graham for the review.

Thanks Collin Anderson for the review.

Thanks django at patrickbregman.eu for the report.

Previously, GET, POST, and FILES on an HttpRequest were created in
the __init__ method as dictionaries. This was not something you would
usually notice causing trouble in production as you'd only see a
WSGIRequest, but in testing using the test client, calling .getlist
on GET, POST, or FILES for a request with no get/post data resulted in
an AttributeError.

Changed GET and POST on an HttpRequest object to be mutable
QueryDicts (mutable because the Django tests, and probably many
third party tests, were expecting it).

``HttpRequest.build_absolute_uri()`` now correctly handles paths starting with ``//``.
``WSGIRequest`` now doesn't remove all the leading slashes either,
because ``http://test/server`` and http://test//server`` aren't the same thing
(RFC2396).

Thanks to SmileyChris for the initial patch.

This commit touchs various parts of the code base and test framework. Any
found usage of opening a cursor for the sake of initializing a connection
has been replaced with 'ensure_connection()'.

Added comments in the three empty models.py files that are still needed.

Adjusted the test runner to add applications corresponding to test
labels to INSTALLED_APPS even when they don't have a models module.

Also added some tests for HttpRequest.__repr__.
Note that the added tests don't actually catch the accidental code
removal (see ticket) but they do cover a codepath that wasn't tested
before.

Thanks to Tom Christie for the report and the original patch.

Thanks manfre for the report and Timo Graham for the review.

Thanks jaylett for the patch.

The documentation promises that host validation is disabled when
DEBUG=True, that all hostnames are accepted. Domains not compliant with
RFC 1034/1035 were however being validated, this validation has now been
removed when DEBUG=True.

Additionally, when DEBUG=False a more detailed SuspiciousOperation
exception message is provided when host validation fails because the
hostname is not RFC 1034/1035 compliant.