main: fix crash by --tcmu-log-dir/-l
Core was generated by `./tcmu-runner -l /var/log'.
Program terminated with signal 11, Segmentation fault.
0x00007f9edc0be8f1 in __strlen_sse2_pminub () from /lib64/libc.so.6
(gdb) where
0x00007f9edc0be8f1 in __strlen_sse2_pminub () at /lib64/libc.so.6
0x0000000000411924 in main (argc=3, argv=0x7ffed1977b78) at
/data/tcmu-runner/main.c:943
(gdb) exit
@@ -934,7 +934,7 @@ int main(int argc, char **argv)
int option_index = 0;
int c, nr_files;
- c = getopt_long(argc, argv, "df:hlV",
+ c = getopt_long(argc, argv, "df:hl:V",
long_options, &option_index);
if (c == -1)
break;
