[COVERITY] Fix memory leak in fsck on error paths

The memory allocated by inst is not reclaimed.  There also was a
call to exit that coverity did not catch the resource leak.  This
might not really be a big issue since the memory will be freed when
fsck exits, but it should be done anyway imho.

Coverity ID: 32: Resource Leak

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2 files changed