Revert "qa/workunits/suites/fsx.sh: don't use zero range"

This reverts commit 583e6e3ef7f28bf34fe038e8a2391f9325a69adf.

We're using a different fsx source, which doesn't support the
same options as our git-based one does.

Signed-off-by: Greg Farnum <greg@inktank.com>