Fix out-of-bounds-read issue.
Fix out-of-bounds-read issue.

Suggested by: philip

* subversion/libsvn_subr/dirent_uri.c
  (canonicalize): check bounds before reading from target
   buffer.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@874306 13f79535-47bb-0310-9956-ffa450edef68

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