Rename a method to match the rcsparse API:
Rename a method to match the rcsparse API:

* tools/cvs2svn/cvs2svn.py
  (CollectData.set_principal_branch): Replace set_default_branch, as
    the rcsparse 'Sink' class expects this name instead.

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