Use a 'hard coded' environment variable to define the search root.

This way it can either be set as an environment variable in a profile
(for when the same value is always used), or it can be overridden on
a command-by-command basis by prefixing the command:

FS_ROOT=/foo fs.sh ...
Suppress inspection warning.
Adjust the shell script to match the FS_ROOT change.
Merge pull request #2 from gkopff/feature/default-env

Feature/default env