[FIX] Packaging: allow publishing releases in --no-testing
[IMP] Packaging: Debian: sign packages with gpg key
[FIX] Packaging: better filename handling

Allow to
1) avoid a special case for debian packages in _publish function
2) publish debian packages with correct filename (ie keeping _amd64, _all)
[FIX] Packaging: RedHat: install in /usr and add systemd unit file

By default, the package was installed in /usr/local/lib/python2.7 in CentOS7.
It is problematic because most of other python packages are installed in /usr/lib
and also because /usr/local/lib is not in the default PYTHONPATH. It's fixed by
overriding the install script and forcing prefix to be /usr.

Added a minimal systemd unitfile.
Adapted tests accordingly.
[FIX] Packaging: RedHat: dependencies management

PyChart is now in the EPEL repo so we now list it as required in
setup.cfg. The other mandatory lib not provided by EPEL are
pyPdf, vatnumber and pydot and are now installed by easy_install
during the post install.
[IMP] Packaging: RedHat: sign packages with gpg key
 [FIX] Packaging: MANIFEST.in: include relevant files

As opposed to before, the source package includes requirements.txt,
LICENCE and the README.md. Note: avoiding to chip openerp.egg-info
leads to weird issues so let's just keep it at the moment.
[FIX] Packaging: lib name from openerp to odoo

It's about time
[FIX] Packaging: batch the signing procedure
[FIX] Packaging: RedHat: (post-)install shell shebang