Merge r896299 from trunk:

clarify that FileETag is for static files only, and explicitly mention 
that ETags aren't generated for files parsed by mod_include.




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@896300 13f79535-47bb-0310-9956-ffa450edef68