fix benchmark entry points
fix benchmark entry points

the classpath was missing, this should make the `check-osc-plugins`
job successfully pass now.

Change-Id: Idaa2ed4ab5452d29a3c826b9e45705a58c65678c

gnocchixyz/python-gnocchiclient,gnocchixyz/python-gnocchiclient,sileht/python-gnocchiclient