Closes #5235
Closes #6370
6.7 Don't clear digest for single realm
6.8 RTSP authentication breaks without redirect support
6.9 SHA-256 digest not supported in Windows SSPI builds
+ 6.10 curl never completes Negotiate over HTTP
7. FTP
7.1 FTP without or slow 220 response
https://github.com/curl/curl/issues/6302
+6.10 curl never completes Negotiate over HTTP
+
+ Apparently it isn't working correctly...?
+
+ See https://github.com/curl/curl/issues/5235
+
7. FTP
7.1 FTP without or slow 220 response