http: improves expect header handling
Now returns a 417 error status or allows for an event listener on
the checkExpectation
event. Before we were ignoring requests that
had misspelled 100-continue
values for expect headers.
This is a quick port of the work done here: https://github.com/nodejs/node-v0.x-archive/pull/7132 by alFReD-NSH with surrounding discussion here: https://github.com/nodejs/node-v0.x-archive/issues/4651
Refs: #2403 (closed)