HTTP/2 has no status message

[BernzSed]

This change allows Koa to be used with Node's http2 module, introduced in Node 8.4.0, which you can use if you launch node with --expose-http2

[codecov]

Codecov Report

Merging #1049 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1049   +/-   ##
=======================================
  Coverage   99.72%   99.72%           
=======================================
  Files           5        5           
  Lines         369      369           
=======================================
  Hits          368      368           
  Misses          1        1

Impacted Files	Coverage Δ
lib/response.js	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 392e8aa...d29136f. Read the comment docs.

[jonathanong]

I believe there was an issue saying that node fixed this. anyone else know?

[dougwilson]

Yes, fixed in Node.js and in 8.5

[BernzSed]

Looks like it's fixed, but it emits a warning. So this PR isn't needed anymore, but it will prevent that warning, if you care about that.

[codecov-io]

Codecov Report

Merging #1049 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1049   +/-   ##
=======================================
  Coverage   99.72%   99.72%           
=======================================
  Files           5        5           
  Lines         369      369           
=======================================
  Hits          368      368           
  Misses          1        1

Impacted Files	Coverage Δ
lib/response.js	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1e81ea3...6d4330b. Read the comment docs.