Detect and use CHUTNEY_PATH in test scripts.
If the user has CHUTNEY_PATH set, respect that value, rather than cloning a local chutney.
Also, if we have a local chutney, then update it in case there have been changes.
If the user has CHUTNEY_PATH set, respect that value, rather than cloning a local chutney.
Also, if we have a local chutney, then update it in case there have been changes.