The enable_service() and disable_service() functions in
https://review.openstack.org/9407 require the functions
file be sourced before stackrc.
* exercise.sh
* samples/local.sh (this will require manual addition to the user's
local.sh if they based it on the sample)
* tools/build_bm.sh
Change-Id: I1bed687867e870bef5748289d712376435a776af