Remove hardcoded /usr/share/cobbler path

Determine the directories to add to sys.path with the inspect module (they
are relative to the current file)
Support for virtualenv out of the box

If cobbler is installed using a virtualenv python it will use (and setup)
this python for its scripts and wsgi processes automatically.

The directory directives are needed on opensuse since it still uses apache 2.2.
Add some logging in cobblerd

cobblerd failed to start and the backtrace is nowhere to be found (here?).
At least log the message so its possible to fix the problem.
Strip the distribution names

On my system platform.linux_distribution() returns "opensuse " for some reason.
Play safe.
Improve regen_ss_file()

 - use python stdlib instead of os.system()
 - always change the owner of the file. Not only on creation.

The os.system() call failed for me because it tried with user apache that does not exist here.
With this code you can see the problem.
Merge pull request #671 from jansenm/mjansen/virtualenv

Mjansen/virtualenv