title: Python os.walk/fnmatch.filter does not find file when in file's current directory
body: <p>I'm trying to recursively walk through a directory and find files that match a certain pattern. The relevant snippet of my code is:</p>
  
  <pre><code>import sys, os, xlrd, fnmatch
  
  for root, dirnames, filenames in os.walk('/myfilepath/'):
  
      for dir in dirnames:
          os.chdir(os.path.join(root, dir))
  
          for filename in fnmatch.filter(filenames, 'filepattern*'):
              print os.path.abspath(filename)
              print os.getcwd()
              print filename
  
              wb = xlrd.open_workbook(filename)
  </code></pre>
  
  <p>My print lines demonstrate that <code>os.getcwd()</code> is equal to the directory of filename, so to me it seems like the file should be found, but <code>IOError: [Errno 2] No such file or directory</code> is thrown for <code>wb = xlrd.open_workbook(filename)</code> when the first pattern is matched.</p>