Fix a broken link.
Fix a broken link.

* notes/subversion-design.html:
  Correct the link which points to webdav usage web page.

Patch by: Azhagu Selvan SP <tamizhgeek@gmail.com>

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion