LP1834208 Update proxy example configuration files

LP1834208 Update proxy example configuration files

The examples/haproxy/osrf-ws-http-proxy file needed a syntax
correction with the listen directive.

Remove X-Real-IP lines from the examples/nginx/osrf-ws-http-proxy
configuration, and remove the X-Client-IP line from the
examples/haproxy/osrf-ws-http-proxy configuration.  These entries are
redundant when X-Forwarded-For is being used.

This latter change also suggests changes in the Evergreen Apache 2
configuration examples.

Signed-off-by: Jason Stephenson <jason@sigio.com>
Signed-off-by: Jason Boyer <jboyer@library.in.gov>
Signed-off-by: Ben Shum <ben@evergreener.net>