Make 'svnserve --help' exit with the status code '0', not '1', because it outputs the help message as expected.
Make 'svnserve --help' exit with the status code '0', not '1', because
it outputs the help message as expected.

* subversion/svnserve/main.c
  (help): Replace 'exit(1)' with 'exit(0)'.

Approved by: julianfoad

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