wininet: Replacing a header with an empty value deletes it.

[testbot at winehq.org]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
http://newtestbot.winehq.org/JobDetails.pl?Key=1918

Your paranoid android.


=== w7pro64 (32 bit http) ===
http.c:4279: Test failed: HttpSendRequest failed: 12057
http.c:4284: Test failed: expected secure flag to be set

=== w7pro64 (64 bit http) ===
http.c:3445: Test failed: HttpQueryInfo failed 0