This reverts commit ddeaf310.

partitions

utils module is imported, not just one method.

For example, on Mandriva, if SECURE_TMP is enabled (in /etc/security/shell),
then TMP/TMPDIR are set to $HOME/tmp but $HOME is only accessible by the owner
and its group, but not slap user, then the extends-cache temporary directory
will not be accessible after dropping the privileges.

Squashed commit of the following:

commit 154041e95f9e6427c274d9c46edbba14ab66b4d6
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 19:05:40 2011 +0200

    Cleanup the code (pyflaked)

commit 4cf44c7f2baf02a056d21b88a4a1a21b534aea75
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 17:17:40 2011 +0200

    Cover passing SSL auth keys to buildout.

commit b8207942ba678f6dd3a34c45c56b100d94a44d87
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 17:14:46 2011 +0200

    Fix typo.

commit 551a3e3c017d83ca1ba4b7a50c66d1a0b847cf8e
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 17:08:39 2011 +0200

    Allow to specify and pass SSL auth key and certs.

If we import the functions directly we are not able to mock the method
it in the proper way as in the previous commit:
 - 2cb7a0f5

This reverts commit 017a02ef.

Conflicts:

	slapos/grid/SlapObject.py

To avoid the explosion of "if" structure, it is better replace it using
a "for" structure.

The behavior of the code still the same.

The new parameter is:
  - upload_authentication_file: the content must be the path of
    SSL key which must be used to make the user authentication in the
    Networkcache HTTP server.

It must be propagated to buildout command line, of course.

Added upload_cache_url and upload_dir_url:
 - upload_cache_url: the value must be the url of shacache used to
   upload
   content.
 - upload_dir_url: the value must be the url of shadir used to upload
   the
   information about the content.

Also, the signature_private_key_file is not required to instanciate a
Software object, then it can be None by default.

All these parameters listed above should only be used in the buildout
command line, if they are not None. And it should be defined under
networkcache-section.

By default the buildout's options are written with '-' instead of '_'.

So, lets keep like that.

Removed the argument signature_public_file because it should be inside
the software profile under networkcache-section.

And renamed signature_private_file to signature_private_key_file.