title: py.test does not start (EBUSY: [Resource device])
body: <p>Just installed py.test with <code>pip install -U pytest</code> with no errors, however we I'm trying to launch <code>py.test</code> I get error: <code>EBUSY: [Resource device]: listdir('C:\\Users\\Administrator\\AppData\\Local\\Application Data',)</code>  </p>
  
  <p>Here is the output:</p>
  
  <pre><code>C:\Users\Administrator&gt;py.test  
  ========================== test session starts ===========================  
  platform win32 -- Python 2.7.3 -- pytest-2.2.4  
  collected 0 items / 1 errors  
  
  ================================= ERRORS =================================
  ___________________________ ERROR collecting . ___________________________  
  C:\Python27\lib\site-packages\py\_path\common.py:315: in visit  
  &gt;       for x in Visitor(fil, rec, ignore, bf, sort).gen(self):  
  C:\Python27\lib\site-packages\py\_path\common.py:361: in gen  
  &gt;               for p in self.gen(subdir):  
  C:\Python27\lib\site-packages\py\_path\common.py:361: in gen  
  &gt;               for p in self.gen(subdir):  
  C:\Python27\lib\site-packages\py\_path\common.py:361: in gen  
  &gt;               for p in self.gen(subdir):  
  C:\Python27\lib\site-packages\py\_path\common.py:346: in gen  
  &gt;           entries = path.listdir()  
  C:\Python27\lib\site-packages\py\_path\local.py:320: in listdir  
  &gt;       for name in py.error.checked_call(os.listdir, self.strpath):  
  C:\Python27\lib\site-packages\py\_error.py:83: in checked_call  
  &gt;           raise cls("%s%r" % (func.__name__, args))  
  E           EBUSY: [Resource device]: listdir('C:\\Users\\Administrator\\Ap 
  pData\\Local\\Application Data',)  
  ======================== 1 error in 0.03 seconds =========================
  </code></pre>
  
  <p>What could that be?</p>
  
  <p>Thanks</p>