ogc proxy: x-forwarded-host header causes problems when proxying some requests.

https://github.com/georchestra/georchestra/issues/782
updated comments.
Merge pull request #839 from jesseeichar/14.01-remove-x-forwarded

ogc proxy: x-forwarded-host header causes problems when proxying some requests.
Merge branch '14.01' into 14.06

Conflicts:
	security-proxy/src/main/filtered-resources/WEB-INF/proxy-servlet.xml