RFR 8175814: HttpClient protocol version needs unspecified value

[Michael McMahon]

Hi

Could I get the following JDK 9 change reviewed, please?
In addition to fixing the spec problem around HTTP version,
it fixes an implementation issue with version also, where the per-request
version (if set) was not being picked up.

http://cr.openjdk.java.net/~michaelm/8175814/webrev.1/index.html

Thanks,

Michael