Allow checkout into a single database; little else works.
Allow checkout into a single database; little else works.

* subversion/libsvn_wc/update_editor.c
  (prep_directory): Don't create database if SINGLE_DB.
  (add_directory): Don't do parent stub stuff if SINGLE_DB.

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