Retry for pip install in tox
Retry for pip install in tox

Make pip retry to download package if installation fails

Change-Id: If395f0ab0d826ad03a1dc856132286f3527d0082

okolisny/InfraRed,okolisny/InfraRed,redhat-openstack/infrared,redhat-openstack/infrared,okolisny/InfraRed,redhat-openstack/infrared