title: Opening zipfile of unsupported compression-type silently returns empty filestream, instead of throwing exception
body: <p>Seem to be knocking my head off a newbie error and I am not a newbie.
  I have a 1.2G known-good zipfile <em>'train.zip'</em> containing a 3.5G file <em>'train.csv'</em>.
  I open the zipfile and file itself without any exceptions (no <em>LargeZipFile</em>), but the resulting filestream appears to be empty. (UNIX <em>'unzip -c ...'</em> confirms it is good)
  The file objects returned by Python <code>ZipFile.open()</code> are not seek'able or tell'able, so I can't check that.</p>
  <p>Python distribution is <em>2.7.3 EPD-free 7.3-1 (32-bit)</em> ; but should be ok for large zips. OS is MacOS 10.6.6</p>
  <pre><code>import csv
  import zipfile as zf
  
  zip_pathname = os.path.join('/my/data/path/.../', 'train.zip')
  #with zf.ZipFile(zip_pathname).open('train.csv') as z:
  z = zf.ZipFile(zip_pathname, 'r', zf.ZIP_DEFLATED, allowZip64=True) # I tried all permutations
  z.debug = 1
  z.testzip() # zipfile integrity is ok
  
  z1 = z.open('train.csv', 'r') # our file keeps coming up empty?
  
  # Check the info to confirm z1 is indeed a valid 3.5Gb file...
  z1i = z.getinfo(file_name)
  for att in ('filename', 'file_size', 'compress_size', 'compress_type', 'date_time',  'CRC', 'comment'):
      print '%s:\t' % att, getattr(z1i,att)
  # ... and it looks ok. compress_type = 9 ok?
  #filename:  train.csv
  #file_size: 3729150126
  #compress_size: 1284613649
  #compress_type: 9
  #date_time: (2012, 8, 20, 15, 30, 4)
  #CRC:   1679210291
  
  # All attempts to read z1 come up empty?!
  # z1.readline() gives ''
  # z1.readlines() gives []
  # z1.read() takes ~60sec but also returns '' ?
  
  # code I would want to run is:
  reader = csv.reader(z1)
  header = reader.next()
  return reader
  </code></pre>