Fix test_local_replace on GNU/Linux

[INFO] [exec] ======================================================================
[INFO] [exec] FAIL: test_local_replace (nxdrive.tests.test_windows.TestWindows)
[INFO] [exec] ----------------------------------------------------------------------
[INFO] [exec] Traceback (most recent call last):
[INFO] [exec] File "/opt/jenkins/workspace/master/FT-nuxeo-drive-master-linux/nuxeo-drive-client/nxdrive/tests/test_windows.py", line 45, in test_local_replace
[INFO] [exec] self.assertEqual(remote.get_content('/test.odt'), 'Some content.')
[INFO] [exec] AssertionError: 'Updated content.' != 'Some content.'