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
rpc_request.debug(logline)
            return self._json_response(result)
        except Exception as e:
            return self._handle_exception(e)
def serialize_exception(e):
    tmp = {
        "name": type(e).__module__ + "." + type(e).__name__ if type(e).__module__ else type(e).__name__,
        "debug": traceback.format_exc(),
        "message": ustr(e),
        "arguments": e.args,
        "exception_type": "internal_error"
    }
    if isinstance(e, odoo.exceptions.UserError):
        tmp["exception_type"] = "user_error"
    elif isinstance(e, odoo.exceptions.Warning):
        tmp["exception_type"] = "warning"
    elif isinstance(e, odoo.exceptions.RedirectWarning):
        tmp["exception_type"] = "warning"
    elif isinstance(e, odoo.exceptions.AccessError):
        tmp["exception_type"] = "access_error"
    elif isinstance(e, odoo.exceptions.MissingError):
        tmp["exception_type"] = "missing_error"
    elif isinstance(e, odoo.exceptions.AccessDenied):
        tmp["exception_type"] = "access_denied"
    elif isinstance(e, odoo.exceptions.ValidationError):
        tmp["exception_type"] = "validation_error"
    elif isinstance(e, odoo.exceptions.except_orm):
        tmp["exception_type"] = "except_orm"
    return tmp
class HttpRequest(WebRequest):