Fix dtests on 2.2 branch on Windows

Traceback (most recent call last):
  File "C:\src\cassandra-dtest\dtest.py", line 452, in tearDown
    self._cleanup_cluster()
  File "C:\src\cassandra-dtest\dtest.py", line 172, in _cleanup_cluster
    self.cluster.remove()
  File "build\bdist.win-amd64\egg\ccmlib\cluster.py", line 212, in remove
    shutil.rmtree(self.get_path())
  File "C:\Python27\lib\shutil.py", line 247, in rmtree
    rmtree(fullname, ignore_errors, onerror)
  File "C:\Python27\lib\shutil.py", line 247, in rmtree
    rmtree(fullname, ignore_errors, onerror)
  File "C:\Python27\lib\shutil.py", line 252, in rmtree
    onerror(os.remove, fullname, sys.exc_info())
  File "C:\Python27\lib\shutil.py", line 250, in rmtree
    os.remove(fullname)
WindowsError: [Error 5] Access is denied: 'c:\\temp\\dtest-4rxq2i\\test\\node1\\commitlogs\\CommitLog-5-1431969131917.log'

06:00:20 ERROR: test_incr_decr_super_remove (thrift_tests.TestMutations)
06:00:20 ----------------------------------------------------------------------
06:00:20 Traceback (most recent call last):
06:00:20   File "D:\jenkins\workspace\trunk_dtest_win32\cassandra-dtest\thrift_tests.py", line 55, in setUp
06:00:20     cluster.start()
06:00:20   File "build\bdist.win-amd64\egg\ccmlib\cluster.py", line 249, in start
06:00:20     p = node.start(update_pid=False, jvm_args=jvm_args, profile_options=profile_options)
06:00:20   File "build\bdist.win-amd64\egg\ccmlib\node.py", line 457, in start
06:00:20     common.check_socket_available(itf)
06:00:20   File "build\bdist.win-amd64\egg\ccmlib\common.py", line 341, in check_socket_available
06:00:20     raise UnavailableSocketError("Inet address %s:%s is not available: %s" % (addr, port, msg))
06:00:20 UnavailableSocketError: Inet address 127.0.0.1:9042 is not available: [Errno 10013] An attempt was made to access a socket in a way forbidden by its access permissions
06:00:20 -------------------- >> begin captured logging << --------------------
06:00:20 dtest: DEBUG: removing ccm cluster test at: d:\temp\dtest-a5iny5
06:00:20 dtest: DEBUG: cluster ccm directory: d:\temp\dtest-dalzcy
06:00:20 --------------------- >> end captured logging << ---------------------