install-deps.sh: robust pip and wheel installation

install-deps.sh: robust pip and wheel installation

The wheel and pip module must not only be installed in each wheelhouse
directory for tox to find. They must also be installed in the virtual
environment that populates the wheelhouse directory. Otherwise older pip
modules such as the one found by default on Ubuntu 12.04 will fail.

Python 2.7.3 on Ubuntu 12.04 also requires that distribute >= 0.7.3 is
installed although it is redundant with setuptools, otherwise it will
fail to run the wheel module.

Signed-off-by: Loic Dachary <ldachary@redhat.com>