SPDY/3: drop the "delayed" flag when finalizing connection

This problem has been fixed for SPDY/2.
More details are available here: http://hg.nginx.org/nginx/rev/a279d2a33dbf
Merge pull request #489 from chobits/master

SPDY/3: drop the "delayed" flag when finalizing connection
Feature: upstream dynamic resolve

This is version 1, the "imperfect" version.

Introduces a new directive with two parameters into upstream context:

Directive:
    *) dynamic_resolve: enables dynamic resolving functionality on an upstream.

Parameters:
    *) fail_timeout=time, specifies how long tengine will not launch
       a dns query if the dns server is down.
    *) fallback=action, specifies what action to take if the dns server is
       considered as "down".

Support:
    *) use the first result of a dns response
    *) fail_timeout
    *) fallback action, but the action "stale" is limited to use what tengine gets
       when it parses the configuration

Not Support:
    *) all results from a dns response
    *) ipv6 address
    *) using stale dns data

All "Not support" stuff are now supported in "perfect" version, which
will be released after tengine is upgraded to original nginx 1.6.x
branch.

Test cases are included.

Signed-off-by: Paul Yang(InfoHunter) <paulyang.inf@gmail.com>
Bugfix: /etc/resolv.conf parsing error with ipv6.
Merge pull request #496 from lifeibo/master

Bugfix: /etc/resolv.conf parsing error with ipv6.
Merge pull request #495 from InfoHunter/dyn-dns

Feature: upstream dynamic resolve
Bugfix: make test case independent

Use www.taobao.com to replace senginx.test in dynamic_resolve.t

Signed-off-by: Paul Yang(InfoHunter) <paulyang.inf@gmail.com>