Fix some byterange handling. If we get a byte range that looks like

"-999999" where that is past the end of the file, we should return
a PARTIAL CONTENT status code, and return the whole file as one big
byterange.  This matches the 1.3 handling now.  [Ryan Bloom]


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@87885 13f79535-47bb-0310-9956-ffa450edef68