Updating the docker file to work

[zacharyestep]

Summary

Had some trouble running the dev setup scripts in the provided docker file environment. They rely on sudo. Made changes.

Test Plan

Run build && test

[CLAassistant]

All committers have signed the CLA.

[zacharyestep]

(closing and reopening for travis rebuild)

[Karmastic]

If you want to fix the dockerfile, please keep this PR focused on that. Addressing the assumptions around GITHUBREPO is a larger change that I would like to consider separately. Your changes only address a fraction of the total scope.

[zacharyestep]

If you want to fix the dockerfile, please keep this PR focused on that. Addressing the assumptions around GITHUBREPO is a larger change that I would like to consider separately. Your changes only address a fraction of the total scope.

Reduced scope as desired. Do you request further changes?

[Karmastic]

Thanks! This works. I'm going to encourage prioritizing support for agile source location - you are correct it is an undue burden requiring a specific root folder location.