title: Rows are lost when reading this tab-separated file with pandas read_csv
body: <p>I have a <code>.text</code> file with following format, where fields (index number, name and message) are separated by <code>\t</code> (tab-separated):</p>
  
  <pre><code>712 ben     Battle of the Books
  713 james   i used to be in TOM
  714 tomy    i was in BOB once
  715 ben Tournaments of Minds
  716 tommy    Also the Lion in the upcoming school play
  717 tommy   Can you guess
  718 tommy    P
  ...
  </code></pre>
  
  <p>which I read with <code>read_csv</code> into a data frame:</p>
  
  <pre><code> chat = pd.read_csv("f.text", sep = "\t", header = None, usecols = [2])
  </code></pre>
  
  <p>But the data frame just has <code>9812</code> rows while the ordinary file has more than <code>12428</code> rows (just 21 empty lines). It is quite weird. Do you have any idea? Thanks.</p>