title: Remove leap year day from pandas dataframe
body: <p>I have the foll. dataframe:</p>
  
  <pre><code>datetime
  2012-01-01    125.5010
  2012-01-02    125.5010
  2012-01-03    125.5010
  2012-02-04    125.5010
  2012-02-05    125.5010
  2012-02-29    125.5010
  2012-02-28    125.5010
  2016-01-07    125.5010
  2016-01-08    125.5010
  2016-02-29     81.6237
  </code></pre>
  
  <p>I would like to drop all rows corresponding to Feb 29th, resulting in foll. data frame:</p>
  
  <pre><code>datetime
  2012-01-01    125.5010
  2012-01-02    125.5010
  2012-01-03    125.5010
  2012-02-04    125.5010
  2012-02-05    125.5010
  2012-02-28    125.5010
  2016-01-07    125.5010
  2016-01-08    125.5010
  </code></pre>
  
  <p>Right now, I am just doing it manually:</p>
  
  <p><code>df.drop(df.index[['2012-02-29']])</code>. How can I make it so that it works for all years, without haveing to manually specify row index.</p>