Rework previous (1.24) change.  Rather than depending on the
file's flags to decide if decompress cleanup is needed, just
check to see if the open() allocated the 'struct sd *' used for
decompression.

This fixes recent problem where presence of a "load=ffs" command
in my /boot.cfg resulted in a "heap full" error at boot time.

OK martin@
remove trailing whitespace
llib-lctf.ln is dtrace specific.