continue clarification of RewriteBase, lots of users who install little

PHP apps with an Alias a) leave off RewriteBase then b) add the filesystem
path instead of the URL-path then c) spend hours trying to debug
the RewriteRules themselves.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@883030 13f79535-47bb-0310-9956-ffa450edef68