title: Resample Length Mismatch Error
body: <p>I get an error when I try to resample the following time series. It seems it fails only with 'MS' resampling. If I add one more row to the time series it goes through w/o any problems. Can figure out what's wrong here :(</p>
  
  <pre><code>dates=[datetime(2014,6,1),datetime(2014,10,1),datetime(2015,2,1)]
  ts=pd.Series([1,1,0],index=dates)
  ts
  
  2014-06-01    1
  2014-10-01    1
  2015-02-01    0
  
  ts.resample('MS')
  
  ValueError: Length mismatch: Expected axis has 3 elements, new values have 9 elements 
  </code></pre>