Fixed segmentation fault in ngx_resolver_create_name_query(). If name passed for resolution was { 0, NULL } (e.g. as a result of name server returning CNAME pointing to ".") pointer wrapped to (void *) -1 resulting in segmentation fault on an attempt to dereference it. Reported by Lanshun Zhou.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_SUPPRESS_WARN . auto/have

have=NGX_SMP . auto/have