Impacted versions: 8-11

## Current behavior:

If during an XMLRPC call you try to get anything from `http.request`, you'd get a `RuntimeError` such as this one:

```
Traceback (most recent call last):
  File "/opt/odoo/custom/src/odoo/odoo/service/wsgi_server.py", line 56, in xmlrpc_return
    result = odoo.http.dispatch_rpc(service, method, params)
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 118, in dispatch_rpc
    result = dispatch(method, params)
  File "/opt/odoo/custom/src/odoo/odoo/service/common.py", line 57, in dispatch
    return g[exp_method_name](*params)
  [...]
  File "/usr/local/lib/python2.7/dist-packages/werkzeug/local.py", line 343, in __getattr__
    return getattr(self._get_current_object(), name)
  File "/usr/local/lib/python2.7/dist-packages/werkzeug/local.py", line 302, in _get_current_object
    return self.__local()
  File "/usr/local/lib/python2.7/dist-packages/werkzeug/local.py", line 135, in _lookup
    raise RuntimeError(\'object unbound\')
RuntimeError: object unbound
```

This renders imposible in practice to fix issues such as https://github.com/OCA/server-tools/issues/1125 or to implement https://github.com/odoo/odoo/pull/22212#issuecomment-380425764.

## Expected behavior:

XML-RPC calls should have request, since after all they belong to one. Otherwise, at least there should be an alternate way to access the request parameters.

Fix for v12: https://github.com/odoo/odoo/pull/24187

@Tecnativa
odoo/http.py
"""Called within an except block to allow converting exceptions
           to arbitrary responses. Anything returned (except None) will
           be used as response."""
        try:
            return super(JsonRequest, self)._handle_exception(exception)
        except Exception:
            if not isinstance(exception, (odoo.exceptions.Warning, SessionExpiredException,
                                          odoo.exceptions.except_orm, werkzeug.exceptions.NotFound)):
                _logger.exception("Exception during JSON request handling.")
            error = {
                    'code': 200,
                    'message': "Odoo Server Error",
                    'data': serialize_exception(exception)
            }
            if isinstance(exception, werkzeug.exceptions.NotFound):
                error['http_status'] = 404
                error['code'] = 404
                error['message'] = "404: Not Found"
            if isinstance(exception, AuthenticationError):
                error['code'] = 100
                error['message'] = "Odoo Session Invalid"
            if isinstance(exception, SessionExpiredException):
                error['code'] = 100
                error['message'] = "Odoo Session Expired"
            return self._json_response(error=error)
    def dispatch(self):