IOError: [Errno 22] invalid mode ('ab') or filename when cp from gsutil

When trying to copy a file from a Google Bucket using gsutil on Windows i am getting the next error:

```
C:\Program Files (x86)\Google\Cloud SDK>gsutil cp -r gs://BUCKET/FOLDER/SOMEFILE.json e:\logs\
Copying gs://BUCKET/FOLDER/SOMEFILE.json... / [0 files][ 0.0 B/ 25.4 KiB]
Traceback (most recent call last):
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform/gsutil \gsutil", line 22, in gsutil.RunMain() File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gsutil.py", line 117, in RunMain sys.exit(gslib.main.main())
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib__main__.py", line 407, in main perf_trace_token=perf_trace_token, user_project=user_project)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib__main__.py", line 590, in _RunNamedCommandAndHandleExceptions user_project=user_project)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\command_runner.py", line 372, in RunNamedCommand return_code = command_inst.RunCommand()
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\commands\cp.py", line 1182, in RunCommand seek_ahead_iterator=seek_ahead_iterator)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\command.py", line 1441, in Apply arg_checker, should_return_results, fail_on_error)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\command.py", line 1512, in _SequentialApply worker_thread.PerformTask(task, self)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\command.py", line 2179, in PerformTask results = task.func(cls, task.args, thread_state=self.thread_gsutil_api)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\commands\cp.py", line 793, in _CopyFuncWrapper preserve_posix=cls.preserve_posix_attrs)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\commands\cp.py", line 990, in CopyFunc gzip_exts=self.gzip_exts, preserve_posix=preserve_posix))
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\utils\copy_helper.py", line 3489, in PerformCopy preserve_posix=preserve_posix)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\utils\copy_helper.py", line 2754, in _DownloadObjectToFile dst_url, src_obj_metadata, logger)
File "C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\platform\gsutil \gslib\utils\copy_helper.py", line 2119, in _GetDownloadFile fp = open(download_file_name, 'ab')
IOError: [Errno 22] invalid mode ('ab') or filename: u'e:\logs\SOMEFILE.json_.gstmp'

C:\Program Files (x86)\Google\Cloud SDK>
```

That error does not happen if using Linux application.