ra_serf: Add 'svndiff1' and 'svndiff' to Accept-Encoding header in update  report request.
ra_serf: Add 'svndiff1' and 'svndiff' to Accept-Encoding header in update 
report request.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1436783 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion