title: Update patch edge colours in Geopandas plot
body: <p>I've plotted a GeoDataFrame as a choropleth using the following code (geopandas 0.2.1, matplotlib 2.0.2, in a Jupyter notebook, using <code>%inline</code>:</p>
  
  <pre><code>fig, ax = plt.subplots(
      1,
      figsize=(16., 12.),
      dpi=100,
      subplot_kw=dict(aspect='equal'),
  )
  
  base = imd_gdf.dropna().plot(
      ax=ax,
      alpha=1.,
      column="Rental_Count",
      scheme="fisher_jenks",
      k=7,
      cmap="viridis",
      linewidth=0.1,
      edgecolor='black',
      legend=True,
  )
  </code></pre>
  
  <p>Which gives me a map with edges around the polygons:</p>
  
  <p><a href="https://i.stack.imgur.com/DGYxB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DGYxB.png" alt="enter image description here"></a></p>
  
  <p>I'd like to remove these. So far, I've tried cycling through the patches, setting the edge colours to the face colours:</p>
  
  <pre><code>for p in ax.patches:
      nc = p.get_facecolor()
      p.set_edgecolor(nc) 
  </code></pre>
  
  <p>But it has no effect, even if I specify a single colour in the loop. Neither <code>p.set_color(nc)</code>, or attempting to set the line width to 0 using <code>p.set_linewidth(0.0)</code> have any effect.
  What am I missing here? Updating the face colour in the same way using <code>p.set_facecolor('white')</code> works fine:</p>
  
  <p><a href="https://i.stack.imgur.com/c29mu.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/c29mu.png" alt="enter image description here"></a></p>