trivial: remove import by URL from data source explanation message

wcs/admin/data_sources.py

@@ -316,8 +316,7 @@ class NamedDataSourcesDirectory(Directory):
         r = TemplateIO(html=True)
         r += htmltext('<h2>%s</h2>') % import_title
         r += htmltext('<p>%s</p>') % _(
-            'You can install a new data source by uploading a file '
-            'or by pointing to the data source URL.')
+            'You can install a new data source by uploading a file.')
         r += form.render()
         return r.getvalue()