The pip install -f flag is for find-links which is a list of locations
to look for python packages. What we hvae at this path for extras
installation is a list of packages themselves not locations to find
them. We need to use the -r flag for requirements lists to specify this
instead.
This change should update our zuul and nodepool images to include useful
debugging extras.
Change-Id: I647bb835d0c85c3772e1593866a54cfc5ea1db2f
45da85124f