title: Drop specific row from a DataFrame with a MultiIndex
body: <p>I have a Dataframe with 2 data columns and a multiindex for every month and every day in a month, so something like:</p>
  
  <pre><code>           temperatureMax  temperatureMin
  time time                                
  1    1          14.167500        7.744167
       2          13.735000        7.480833
       3          14.228333        7.901667
       4          13.891667        7.350833
       5          13.735833        6.903333
       6          13.670000        6.494167
       7          13.642500        7.040000
       8          13.005000        6.175000
       9          13.034167        5.253333
       10         13.260833        5.628333
       11         13.783333        5.511667
       12         13.823333        6.630000
       13         13.265833        6.712500
       14         13.112500        6.130000
       15         12.355833        7.213333
       16         13.032500        6.533333
       17         13.175833        7.030000
       18         13.184167        8.225000
       19         13.896667        6.658333
       20         13.711667        5.693333
       21         13.442500        5.944167
       22         13.245000        6.468333
       23         13.765000        5.555833
       24         14.260000        5.212500
       25         13.523333        5.850000
       26         13.000000        5.519167
       27         12.554167        5.264167
       28         12.806667        5.311667
       29         12.755000        6.012500
       30         13.240833        6.136667
  ...                   ...             ...
  12   2          13.545000        5.855833
       3          14.380833        6.214167
       4          14.502500        7.610833
       5          15.379167        8.201667
       6          15.161667        8.593333
       7          15.101667        8.940833
       8          14.886667        7.217500
       9          14.701667        7.680000
       10         14.756667        7.160000
       11         14.575000        6.057500
       12         14.172500        7.138333
       13         14.360833        7.244167
       14         14.285833        7.430000
       15         13.545000        6.167500
       16         14.082500        5.516667
       17         13.780833        5.871667
       18         13.345833        5.357500
       19         13.909167        5.682500
       20         13.264167        5.570833
       21         14.828333        6.620833
       22         14.431667        6.689167
       23         13.564167        6.491667
       24         14.343333        6.074167
       25         13.470000        5.594167
       26         13.468333        4.400833
       27         13.403333        5.600833
       28         14.506667        7.085833
       29         14.173333        6.999167
       30         14.211667        7.810000
       31         13.604167        7.382500
  
  [366 rows x 2 columns]
  </code></pre>
  
  <p>How can I remove a specific day of the month? Namely, I want to remove the 29th of February from this list.</p>
  
  <p>The only thing I can do is to remove every 29th day of every 12 month with <code>daily_mean.drop(29, level=1)</code>, but I want to do that only for February.</p>