Cartopy fails to download coastlines

[alimanfoo]

In the collection sites notebook, when plotting map with ecosystems, we get this:

/usr/local/lib/python3.7/dist-packages/cartopy/io/__init__.py:241: DownloadWarning: Downloading: https://naciscdn.org/naturalearth/50m/physical/ne_50m_coastline.zip
  warnings.warn('Downloading: {}'.format(url), DownloadWarning)
Error in callback <function install_repl_displayhook.<locals>.post_execute at 0x7f9194308ef0> (for post_execute):
---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
/usr/lib/python3.7/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
   1349                 h.request(req.get_method(), req.selector, req.data, headers,
-> 1350                           encode_chunked=req.has_header('Transfer-encoding'))
   1351             except OSError as err: # timeout error

35 frames
gaierror: [Errno -3] Temporary failure in name resolution

During handling of the above exception, another exception occurred:

URLError                                  Traceback (most recent call last)
/usr/lib/python3.7/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
   1350                           encode_chunked=req.has_header('Transfer-encoding'))
   1351             except OSError as err: # timeout error
-> 1352                 raise URLError(err)
   1353             r = h.getresponse()
   1354         except:

URLError: <urlopen error [Errno -3] Temporary failure in name resolution>
---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
/usr/lib/python3.7/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
   1349                 h.request(req.get_method(), req.selector, req.data, headers,
-> 1350                           encode_chunked=req.has_header('Transfer-encoding'))
   1351             except OSError as err: # timeout error

35 frames
gaierror: [Errno -3] Temporary failure in name resolution

During handling of the above exception, another exception occurred:

URLError                                  Traceback (most recent call last)
/usr/lib/python3.7/urllib/request.py in do_open(self, http_class, req, **http_conn_args)
   1350                           encode_chunked=req.has_header('Transfer-encoding'))
   1351             except OSError as err: # timeout error
-> 1352                 raise URLError(err)
   1353             r = h.getresponse()
   1354         except:

URLError: <urlopen error [Errno -3] Temporary failure in name resolution>
<Figure size 504x504 with 1 Axes>

[alimanfoo]

Fixed.