zopewsgi: enable HTTPExceptionHandler

This middleware is enabled in Zope's mkwsginstance [1] and also in test,
[2], we should also enable it here for consistency.

It is necessary to handle exceptions when no standard_error_message
skin exists, like it is the case today in RJS skin selection.

1: https://github.com/zopefoundation/Zope/blob/828b1973e39f4dc1bf51fea0cd11a236d28ec3b5/src/Zope2/utilities/skel/etc/zope.ini.in#L16
2: https://github.com/zopefoundation/Zope/blob/828b1973e39f4dc1bf51fea0cd11a236d28ec3b5/src/Testing/ZopeTestCase/functional.py#L136

product/ERP5/bin/zopewsgi.py

@@ -23,9 +23,12 @@ from Zope2.Startup.run import make_wsgi_app
 try:
   from ZPublisher.WSGIPublisher import _MODULES
   from ZPublisher.WSGIPublisher import publish_module
+  from ZPublisher.httpexceptions import HTTPExceptionHandler
 except ImportError:
   # BBB Zope2
   from Products.ERP5Type.patches.WSGIPublisher import publish_module
+  HTTPExceptionHandler = lambda app: app
+
 
 # this class licensed under the MIT license (stolen from pyramid_translogger)
 class TransLogger(object):
@@ -141,7 +144,7 @@ def app_wrapper(large_file_threshold, webdav_ports):
                 environ['PATH_INFO'] = path_info
 
         return publish_module(environ, start_response)
-    return app
+    return HTTPExceptionHandler(app)
 
 def createServer(application, logger, **kw):
     global server