Replace automatic ETag generation with configurable algorithm
	defined by FileETag directive.  Keywords are All, None,
	[+|-]INode, [+|-]Size, [+|-]MTime.  Server farms with content
	fanout may want to use 'FileETag MTime Size' to keep the system-
	variant inode from being included and busting caches.
PR:		7010
Submitted by:	Based on an idea proposed by Phil Dietz


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@92738 13f79535-47bb-0310-9956-ffa450edef68