hgdemandimport: exclude more sqlalchemy modules

We could potentially exclude the entire sqlalchemy library.

hgdemandimport/__init__.py

@@ -52,6 +52,7 b' IGNORES = {'
     'rfc822',
     'mimetools',
     'sqlalchemy.events',  # has import-time side effects (issue5085)
+    'sqlalchemy.dialects',  # similar problems as above
     # setuptools 8 expects this module to explode early when not on windows
     'distutils.msvc9compiler',
     '__builtin__',