Add test for fail on locking a non-existent file.
Add test for fail on locking a non-existent file.

Patch by: Alexander Thomas <alexander@collab.net>
(Tweaked by me.)

* subversion/tests/clients/cmdline/lock_tests.py
  (lock_non_existent_file): Added function to test failure on locking
  of non-existent file.

  (test_list): Added lock_non_existent_file to list of tests.

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