Now that the external repository management is done in pip-install
role, we don't need this wiring anymore.
Everything will be consistent across all the roles that include
pip-install.
Change-Id: I30e06acb2762707f77af48e71097e10e18ee3053
Signed-off-by: Jean-Philippe Evrard <jean-philippe@evrard.me>
(Manual backport from commit b6992d31d2)