smb3: don't set rc when used and unneeded in query_info_compound

rc is not checked so should not be set coming back from open_cached_dir
(the cfid pointer is checked instead to see if open_cached_dir failed)

Addresses-Coverity: 1518021 ("Code maintainability issues  (UNUSED_VALUE)")
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>