ensure inigo test rootfs matches cflinuxfs3
ensure inigo test rootfs matches cflinuxfs3

vizzini has changed to expect cflinuxfs3 and the inigo test rootfs is
used in DUSTS so we need to make them match

[#165459289](https://www.pivotaltracker.com/story/show/165459289)

Co-authored-by: Sunjay Bhatia <df2d57be7987a471915f625a5499155bc16d4200@pivotal.io>

cloudfoundry-incubator/diego-dockerfiles,cloudfoundry-incubator/diego-dockerfiles