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
session_gc(self.session_store)
        sid = httprequest.args.get('session_id')
        explicit_session = True
        if not sid:
            sid =  httprequest.headers.get("X-Openerp-Session-Id")
        if not sid:
            sid = httprequest.cookies.get('session_id')
            explicit_session = False
        if sid is None:
            httprequest.session = self.session_store.new()
        else:
            httprequest.session = self.session_store.get(sid)
        return explicit_session
    def setup_db(self, httprequest):
        db = httprequest.session.db
        
        if db:
            if db not in db_filter([db], httprequest=httprequest):
                _logger.warn("Logged into database '%s', but dbfilter "
                             "rejects it; logging session out.", db)
                httprequest.session.logout()
                db = None
        if not db:
            httprequest.session.db = db_monodb(httprequest)
    def setup_lang(self, httprequest):