Fix userland resource leaks

Coverity caught these. With the exception of the file descriptor leak in
tests/zfs-tests/cmd/draid.c, they are all memory leaks.

Also, there is a piece of dead code in zfs_get_enclosure_sysfs_path().
We delete it as cleanup.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13921

cmd/zpool/zpool_main.c

@@ -1196,6 +1196,7 @@ zpool_do_remove(int argc, char **argv)
 		return (1);
 
 	if (stop && noop) {
+		zpool_close(zhp);
 		(void) fprintf(stderr, gettext("stop request ignored\n"));
 		return (0);
 	}