Follow-up to r1464416, fix minor error which occurs during ra_serf test
setup in a clean build environment:

C:\SVN\src-branch-1.8.x-2>win-tests.py -r -f bdb --httpd-dir C:\Apache22
  --httpd-port 7829 -u http://127.0.0.1:7829 -c
Adding password for user jrandom
Adding password for user jconstant
Traceback (most recent call last):
  File "C:\SVN\src-branch-1.8.x-2\win-tests.py", line 736, in <module>
    http_bulk_updates)
  File "C:\SVN\src-branch-1.8.x-2\win-tests.py", line 498, in __init__
    self._create_dontdothat_file()
  File "C:\SVN\src-branch-1.8.x-2\win-tests.py", line 603, in 
_create_dontdothat_file
    fp = open(self.dontdothat_file, 'w')
IOError: [Errno 2] No such file or directory: 
'C:\\SVN\\src-branch-1.8.x-2\\Release\\subversion\\tests\\cmdline\\
  svn-test-work\\dontdothat'
Httpd.stop_daemon not implemented

* win-tests.py
  (Httpd._create_dontdothat_file): Don't assume the 'svn-test-work' directory
   already exists, it won't if you are running the tests for the first time
   in a given environment.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1490679 13f79535-47bb-0310-9956-ffa450edef68