tests: [cpuset] call free() for range

The free() before exit() is not so important, but let's keep the
example code nice and consistent.

Reported-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

lib/cpuset.c

@@ -366,6 +366,7 @@ int main(int argc, char *argv[])
 	printf("[%s]\n", cpulist_create(buf, buflen, set, setsize));
 
 	free(buf);
+	free(range);
 	cpuset_free(set);
 
 	return EXIT_SUCCESS;