New test to exercise multiple path lock/unlock where one path 
has a pre- hook failure.

* subversion/tests/cmdline/lock_tests.py
  (many_locks_hooks): New test.
  (test_list): Add new test.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1584336 13f79535-47bb-0310-9956-ffa450edef68