Allow the user to set the `/etc/salt` directory path through an environment variable. Refs #85.

This is needed for example for BSD based installations for which the value should be `/usr/local/etc/salt`.
Merge pull request #92 from s0undt3ch/hotfix/configurable-etc-dir

Allow the user to set the `/etc/salt` directory path through an environment variable
Merge branch 'develop' of github.com:saltstack/salt-bootstrap into develop
Try to get more information out of the system when the daemons are not found running.