[FIX] http: do not redirect to database manager on registry crash

Before this commit if the loading of the registry failed because of an
AttributeError or a psycopg2 error the http dispatcher would redirect
the user to the database manager.

This can be problematic because integrators (e.g. odoo.sh) may choose to
disable / forbid access to the database manager, and when the registry
crashes because of e.g. a migration, the real error will be overshadowed
by an AccessDenied error or somesuch depending on the path taken to
forbid access to the database manager.

With this commit, the real exception is simply reraised

closes odoo/odoo#49238

X-original-commit: de4e67dcc52916337251370387aea6aea893a60e
Signed-off-by: Raphael Collet (rco) <rco@openerp.com>

odoo/http.py

@@ -1438,10 +1438,11 @@ class Root(object):
                         # - the database version doesnt match the server version
                         # Log the user out and fall back to nodb
                         request.session.logout()
-                        # If requesting /web this will loop
                         if request.httprequest.path == '/web':
-                            result = werkzeug.utils.redirect('/web/database/selector')
+                            # Internal Server Error
+                            raise
                         else:
+                            # If requesting /web this will loop
                             result = _dispatch_nodb()
                     else:
                         result = ir_http._dispatch()