Limit req: fix of rbtree node insertion on hash collisions.

The rbtree used in ngx_http_limit_req_module has two level of keys, the top is
hash, and the next is the value string itself. However, when inserting a new
node, only hash has been set, while the value string has been left empty.

The bug was introduced in r4419 (1.1.14).
Found by Charles Chen.

Fixed strict aliasing bugs when dealing with IPv4-mapped IPv6
addresses.

The "include" directive should be able to include multiple files if
given a filename mask.  Fixed this to work for "include" directives
inside the "map" or "types" blocks.  The "include" directive inside
the "geo" block is still not fixed.

The bug had appeared in 0.8.43 (r3653).  Patch by Weibin Yao.

Previous code incorrectly used ctx->var_values as an array of pointers to
ngx_http_variable_value_t, but the array contains structures, not pointers.
Additionally, ctx->var_values inspection failed to properly set var on
match.

*) Resolver: fixed possible memory leak in ngx_resolver_create().

*) Explicitly ignore returned value from unlink() in ngx_open_tempfile().

*) Explicitly ignore returned value from close() in ngx_event_core_init_conf().

*) Added three missing checks for NULL after ngx_array_push() calls.

*) Crypt: fixed handling of corrupted SSHA entries in password file.

*) Mark logically dead code with corresponding comment.

Found by / prodded by Coverity.

*) Reorder checks in ngx_shared_memory_add() for more consistent
   error messages.

*) Added "const" to ngx_memcpy() with NGX_MEMCPY_LIMIT defined.  This
   fixes warning produced during compilation of the ngx_http_geoip_module
   due to const qualifier being discarded.

*) Fixed possible use of old cached times if runtime went backwards.

   If ngx_time_sigsafe_update() updated only ngx_cached_err_log_time, and
   then clock was adjusted backwards, the cached_time[slot].sec might
   accidentally match current seconds on next ngx_time_update() call,
   resulting in various cached times not being updated.

   Fix is to clear the cached_time[slot].sec to explicitly mark cached times
   are stale and need updating.

*) Radix tree preallocation fix.  The preallocation size was calculated
   incorrectly and was always 8 due to sizeof(ngx_radix_tree_t) accidentally
   used instead of sizeof(ngx_radix_node_t).

*) Fixed overflow if ngx_slab_alloc() is called with very big "size"
   argument.

*) Write filter: replaced unneeded loop with one to free chains.
   Noted by Gabor Lekeny.

The ngx_http_find_virtual_server() function should return NGX_DECLINED
if virtual server not found.

Hide headers and pass headers arrays might not be inherited correctly
into a nested location, e.g. in configuration like

    server {
        proxy_hide_header X-Foo;
        location / {
            location /nested/ {
                proxy_pass_header X-Pad;
            }
        }
    }

the X-Foo header wasn't hidden in the location /nested/.

Reported by Konstantin Svist,
http://mailman.nginx.org/pipermail/nginx-ru/2012-July/047555.html