http: Allow running without admin HTTP server (#4486)
http: Allow running without admin HTTP server (#4486)

Accept bootstrap configs that don't specify an admin port, and simply
don't run the admin server in that case.

Signed-off-by: Fred Douglas <fredlas@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 0fb5efc50ef2b03ab0073f947ebfcf886c4a32b1

lyft/envoy-api,lyft/envoy-api,lyft/envoy-api