Follow-up to r19700 with a test for issue #2552.
Follow-up to r19700 with a test for issue #2552.

Verify that when passing --limit <= 0 to svn log, svn returns with an error.

* subversion/tests/cmdline/log_tests.py
  (log_limit): add test cases for limit=0 and limit=-1.

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