*) Upstream: only call peer.free() if peer.get() selected a peer.

*) Upstream: removed double-free workarounds in peer.free() methods.

Split clients: check length when parsing configuration.

Fixed language in a comment preceding ngx_http_index_handler().

Upstream: call ngx_http_run_posted_requests() on resolve errors.

If proxy_pass to a host with dynamic resolution was used to handle
a subrequest, and host resolution failed, the main request wasn't run
till something else happened on the connection.  E.g. request to "/zzz"
with the following configuration hanged:

    addition_types *;
    resolver 8.8.8.8;

    location /test {
        set $ihost xxx;
        proxy_pass http://$ihost;
    }

    location /zzz {
        add_after_body /test;
        return 200 "test";
    }

Report and original version of the patch by Lanshun Zhou,
http://mailman.nginx.org/pipermail/nginx-devel/2013-March/003476.html.

*) Removed unused prototype of ngx_http_find_server_conf().
   This function prototype and its implementation was added in r90,
   but the implementation was removed in r97.

*) Removed unused ngx_http_clear_variable() macro.

Mp4: fixed handling of too small mdat atoms (ticket #266).

Patch by Gernot Vormayr (with minor changes).

Fixed potential segfault in ngx_http_keepalive_handler().

In case of error in the read event handling we close a connection
by calling ngx_http_close_connection(), that also destroys connection
pool. Thereafter, an attempt to free a buffer (added in r4892) that
was allocated from the pool could cause SIGSEGV and is meaningless
as well (the buffer already freed with the pool).

It was added in r2717 and no longer needed since r2721,
where the termination was added to ngx_shm_alloc() and
ngx_init_zone_pool().  Since then it only corrupted error
messages about invalid zones.

Fixed false memset warning on Linux with -O3 (ticket #275).

Prodded by John Leach.