Bring some envvar flexibility from mod_authnz_fcgi to mod_proxy_fcgi:

mod_proxy_fcgi: Remove 64K limit on encoded length of all envvars.
An individual envvar with an encoded length of more than 16K will be
omitted.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1525276 13f79535-47bb-0310-9956-ffa450edef68