With fixing of EA leak, sanity.sh and sanityN.sh both pass all the way through.

With fixing of EA leak, sanity.sh and sanityN.sh both pass all the way through.
We also pass acceptance-small.sh all the way through (even on a single 72MB
UML) for THREADS=2 SIZE=10240, and will likely pass for the default if run on
a system with more memory.

Sadly (very sadly), nobody noticed that I broke sanityN.sh last week, until
I did this morning.  Nobody ever noticed that "opendevunlink" was actually
compiled from opendirunlink.c until today (not me either).

Updated sanityN.sh to allow single tests to be run, like sanity.sh.
Added checks to both to ensure we have correct config for current mount.
It could be smarter about not needing a config if running with START=:
CLEAN=:, but I leave that for another day.