s3:torture: Initialize pointer with NULL

s3:torture: Initialize pointer with NULL

source3/torture/torture.c:4309:17: error: ‘pname’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
 4309 |                 printf("qfilename gave different name? [%s] [%s]\n",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 4310 |                        fname, pname);
      |                        ~~~~~~~~~~~~~

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sat Dec 11 00:25:46 UTC 2021 on sn-devel-184