Install fail on Ubuntu, sudo not needed for pip

[Whytehorse]

The install instructions for openbazaar server on Ubuntu say to run: sudo -H pip install -r requirements.txt This gives the following error: pkg_resources.DistributionNotFound: The 'pip==9.0.1' distribution was not found and is required by the application

Running without sudo -H fixes this but requires --user as follows: pip install -r requirements.txt --user