gddo-server: remove RedirectHost field from gddoEvent

With golang.org/cl/242097, the teeproxy no longer needs
the RedirectHost field from gddoEvent.

Change-Id: Iaf1647d7939084b2bf2d41816d259c7c274283dc
Reviewed-on: https://go-review.googlesource.com/c/gddo/+/242098
Reviewed-by: Jonathan Amsterdam <jba@google.com>
2 files changed