* Make reverse proxy TLS server name replaceable for SNI upstreams.
* Reverted previous TLS server name replacement, and implemented thread safe version.
* Move TLS servername replacement into it's own function
* Moved SNI servername replacement into httptransport.
* Solve issue when dynamic upstreams use wrong protocol upstream.
* Revert previous commit.
Old commit was: Solve issue when dynamic upstreams use wrong protocol upstream.
Id: 3c9806ccb6
Co-authored-by: Matt Holt <mholt@users.noreply.github.com>