Tweak best-practices doc.
Tweak best-practices doc.

* doc/user/svn-best-practices.html:  clarify what we mean by 'large
  file'.  add some discussion to 'never branch' scenario.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@849520 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion