Fix cherrypy CherryPyWSGIServer import (#301)

CherryPy changed the import location.
This attempts the new or falls back to the old location.

Co-authored-by: Tiemen Schuijbroek <t.j.l.schuijbroek@ratio-case.nl>

pypiserver/bottle.py

@@ -2792,7 +2792,10 @@ class WSGIRefServer(ServerAdapter):
 
 class CherryPyServer(ServerAdapter):
     def run(self, handler): # pragma: no cover
-        from cherrypy import wsgiserver
+        try:
+            from cheroot.wsgi import Server as CherryPyWSGIServer
+        except ImportError:
+            from cherrypy.wsgiserver import CherryPyWSGIServer
         self.options['bind_addr'] = (self.host, self.port)
         self.options['wsgi_app'] = handler
 
@@ -2803,7 +2806,7 @@ class CherryPyServer(ServerAdapter):
         if keyfile:
             del self.options['keyfile']
 
-        server = wsgiserver.CherryPyWSGIServer(**self.options)
+        server = CherryPyWSGIServer(**self.options)
         if certfile:
             server.ssl_certificate = certfile
         if keyfile: