Assorted coverity fixes
dir can be NULL in case of wrong network syntax. Ensure permissions are tested only on non-NULL path.
Detected by coverity scan, I think it is valid.
8. bind-9.16.23/bin/named/server.c:7602: var_compare_op: Comparing "dir" to null implies that "dir" might be null.
10. bind-9.16.23/bin/named/server.c:7612: var_deref_model: Passing null pointer "dir" to "isc_file_isdirwritable", which dereferences it.
# 7610| return (result);
# 7611| }
# 7612|-> if (!isc_file_isdirwritable(dir)) {
# 7613| isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
# 7614| NAMED_LOGMODULE_SERVER, ISC_LOG_ERROR,
Edited by Petr Špaček