Allow mod_authnz_ldap to set environment variables when it only performs authorization.

AuthLDAPAuthorizePrefix can be used to force this to overlap with the prefix used
for authentication.

PR 45584


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@949336 13f79535-47bb-0310-9956-ffa450edef68