python-pyroute2: bump to 0.3.15

Add a hash file.

Change download location to pypi and remove a pre-configure
hook as the package now provides a stand-alone setup.py.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>