Fixed ngx_parse_time() out of bounds access (ticket #821). The code failed to ensure that "s" is within the buffer passed for parsing when checking for "ms", and this resulted in unexpected errors when parsing non-null-terminated strings with trailing "m". The bug manifested itself when the expires directive was used with variables. Found by Roman Arutyunyan.

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


have=NGX_SUPPRESS_WARN . auto/have

have=NGX_SMP . auto/have