setup-environment-internal: machine selection fallbacks
setup-environment-internal: machine selection fallbacks

Fall back to trying "dialog" if the user does not have whiptail installed.

Signed-off-by: Trevor Woerner <8835777cd84fba3d7873eabbbe1f2de2d3f25b00@gmail.com>

twoerner/angstrom-manifest,ndechesne/qcom-oe-manifest,Angstrom-distribution/angstrom-manifest,96boards/oe-rpb-manifest,linaro-home/lhg-oe-manifests,koenkooi/angstrom-manifest