django.conf.urls.defaults was removed.

Import stuff from django.conf.urls instead. If we need to support django versions less than 1.4
then we need some compatibility stuff here.

Since 1.4 deprecated and moved to the new location.
https://docs.djangoproject.com/en/1.4/releases/1.4/#django-conf-urls-defaults

Removed in 1.6
https://docs.djangoproject.com/en/1.6/internals/deprecation/
Revert "Cleanup PXE files for systems that have netboot disabled. Fixes #618"

This reverts commit bcec38e097c1d8563503309f0c81402cf09bf4f2.

This change destroyed the functionality provided by pxe_just_once and
netboot-enabled:
The reason the pxe files are left is so that the machines are commanded,
via pxe, to boot from the local drive. Once the pxe files are deleted,
each machine will now boot using whatever is in /tftboot/.../default,
which is NOT what should happen. The netboot-enabled flag has no control
of the individual bios configs on the machines, the whole idea if
netboot-enabled is that if a machine does pxe-boot but is disabled,
no installation is attempted.

I suggest this feature be rethought, and when added done so in a way
that is guaranteed to not impact existing users and to guarantee that
a machine with netboot-enable = false will be forced to boot from
the local drive.
cobbler.spec - don't overwrite generated files

Commits f550ad5485430ee7c6bd7554a0fe4a45456d7b49 and
9eb1f39df9d9c430cc30fadd271a6df69f21ce43, changed the httpd/*.conf
and cobblerd.service files to be generated. Include the
generated versions into the rpms.
Merge pull request #685 from mark987/issue_618

Revert "Cleanup PXE files for systems that have netboot disabled. Fixes ...
Merge pull request #684 from mark987/fix-rpm-httpd

cobbler.spec - don't overwrite generated httpd files
Merge pull request #666 from jansenm/mjansen/django-compat

django.conf.urls.defaults was removed.