promote TS-1912 and clone as TS-1918

as a side-note, we have noted that this is process is stupid.
We should clone as soon as we propose: If something goes wrong, we can
close that new issue as invalid, but one way or the other, we can track
votes in the NEW issue, not in the old one, which was the whole point of
cloning them in the first place.
TS-1918: SSL hangs after origin handshake

When using SSL with a Netscaler origin, I'm seeing the handshake
complete but ATS never issuing the HTTP request. It seems that while
the handshake is in progress, the write to the origin is not
rescheduled, so ATS never notices that it can send the origin
request.

Conflicts:
	CHANGES

test/review: jpeach, igalic, zwoop
backport: igalic