Remove sudo from mkdir in $STACK_USER folder
Remove sudo from mkdir in $STACK_USER folder

This fails in the environment where sudo does not have permissions to
write in /home/$USER folder, e.g. [1]

Also clean-up the comment/variable usage a bit; the location isn't
actually variable at all (and that's fine, but we don't need a global
here)

[1] http://144.76.193.39/ci-artifacts/228979/10/Nova-ML2-Sriov/console.html.gz

Change-Id: I6807eae9d1c27219aa7c19de29f24fa851aa787c

dirkmueller/devstack,richliu/devstack,group-policy/devstack,noironetworks/devstack,mssumanth/devstack,dirkmueller/devstack,thomasem/devstack,nawawi/openstack,bigswitch/devstack,bswartz/devstack,mssumanth/devstack,nawawi/openstack,varunarya10/devstack,thomasem/devstack,openstack-dev/devstack,samgoon/devstack,richliu/devstack,openstack-dev/devstack,noironetworks/devstack,bigswitch/devstack,group-policy/devstack,dtroyer/devstack,Mahito/devstack,Mahito/devstack,samgoon/devstack,varunarya10/devstack,avvocatodemarchis/devstack,bswartz/devstack,dtroyer/devstack,prithivm/branch01,prithivm/branch01,avvocatodemarchis/devstack