As per Microsoft documentation, Windows authentication
(NTLM/Kerberos/Negotiate) is not supported with HTTP/2.
This patch disables transparent HTTP/2 support when the
vendor setting is "sharepoint-ntlm". Otherwise connections
to IIS/10.0 can fail with HTTP_1_1_REQUIRED.
Co-authored-by: Georg Neugschwandtner <georg.neugschwandtner@gmx.net>