blog: Post for v0.11.9
events: fix TypeError in removeAllListeners

Check that `listeners` is actually an array before trying to manipulate it
because it won't be if no regular event listeners have been registered yet
but there are 'removeListener' event listeners.
doc: clarify child_process error behaviour

Clarify that an 'error' event may or may not be followed by an 'exit'
event and that it's not safe to make assumptions either way.
tls: add serialNumber to getPeerCertificate()

Add a 'serialNumber' property to the object that is returned by
tls.CryptoStream#getPeerCertificate().  Contains the certificate's
serial number encoded as a hex string.  The format is identical to
`openssl x509 -serial -in path/to/certificate`.

Fixes #6583.
blog: npm outage postmortem
Merge remote-tracking branch 'upstream/v0.10'
openssl: more asm
test: use os.EOL when checking output
http: fix parser double-free in _http_client.js

HTTP Parser instance was freed twice, leading to the reusal of it
in several different requests simultaneously.

The flow:

`socketCloseListener` is firing, which calls `socket.read()` to flush
any queued data, `socket.buffer` has data which emits and fires
`socketOnData` in sync, this triggers a parser error which frees the
parser, `socketCloseListener` resumes execution only to have the wrong
parser associated with the socket.

The fix is to only cache the parser after the flushing from the socket,
and to assert in `socketOnData` that `socket === parser.socket`

fix #6451