Fix breakage when distribute is not installed

This fixes a typo in the fallback code, and also allows us to set an
environment variable so the fallback code can be triggered (For testing
purposes)

Change-Id: I5e12b188aa130a5bf71dbdf00b4862eef9115d9f
Reviewed-on: http://review.couchbase.org/27070
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Mordechai Nunberg <mnunberg@haskalah.org>