nghttp2 @0.7.11_0: update to version 0.7.12

[Schamschula (Marius Schamschula)]

nghttp2 has been updated to version 0.7.12:

Implements h2-14 protocol (http://tools.ietf.org/html/draft-ietf-httpbis-http2-14)
Implements HPACK 09 (http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-09)
Fix bug that nghttp2_session_set_next_stream_id accepts invalid stream_id
HPACK: Rewrite static header table handling
HPACK: Never index authorization and small cookie header field
Don't install libnghttp2_asio headers if they are disabled
doc: Specify program directive so that hyperlink to option is correctly pointed to the intended location
asio: client: Call error_cb on error occurred in do_read and do_write (Fixes GH-207)
nghttp: Add --no-push option to disable server push
nghttp: Show stream ID in statistics output
nghttp: Remove --dep-idle option
nghttp: Use same priority anchor nodes as Firefox does
nghttpx: Don't push resource if link header has non empty loadpolicy
nghttpx: Add logging for somewhat important events (logs, tickets, and ocsp)
nghttpx: Set Downstream to stream user data on HTTP Upgrade to h2

[Ionic (Mihai Moldovan)]

Committed as r135239. Thanks!