Add a docs remark about "SSLOptions StdEnvVars"

being not necessary for mod_rewrite
"%{SSL:VARIABLE}" feature and for the mod_ssl
extensions to mod_log_config (%{VARIABLE}x).

CTR
Backport of r1706989 from trunk resp. r1707123
from 2.4.x.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1707153 13f79535-47bb-0310-9956-ffa450edef68