veyron/...: Consolidate use of environment variables into named
constants.

There are still some strings left in the "playground" repository.
I'll switch those over once this commit is in.

Change-Id: Iad72c31f4a1b839d6469f7589967a9f5cf1f1f97
13 files changed
tree: 25a6d50d5b8fa9f636237f96d93e33bbb0be3d00
  1. lib/
  2. profiles/
  3. runtimes/
  4. security/
  5. services/
  6. tools/