[FIX] auth_oauth: set values when necessary

If the record with the external id 'auth_oauth.provider_google' does
not exist in the database, 'google_provider' variable will contains
None.
Before this commit, calling get and set methods produced an error.

After this commit, trying to set a token for Google Authentication
will do nothing.
While this is not ideal, one can assume somebody that deleted an OAuth
provider rarely wants to configure it and can still upgrade the module
to get it back.

closes odoo/odoo#45566

X-original-commit: eca90a31d0d3667cf63994d34c5d2bb81bfd45c4
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

addons/auth_oauth/models/res_config_settings.py

@@ -23,7 +23,7 @@ class ResConfigSettings(models.TransientModel):
     def get_values(self):
         res = super(ResConfigSettings, self).get_values()
         google_provider = self.env.ref('auth_oauth.provider_google', False)
-        res.update(
+        google_provider and res.update(
             auth_oauth_google_enabled=google_provider.enabled,
             auth_oauth_google_client_id=google_provider.client_id,
             server_uri_google=self.get_uri(),
@@ -33,7 +33,7 @@ class ResConfigSettings(models.TransientModel):
     def set_values(self):
         super(ResConfigSettings, self).set_values()
         google_provider = self.env.ref('auth_oauth.provider_google', False)
-        google_provider.write({
+        google_provider and google_provider.write({
             'enabled': self.auth_oauth_google_enabled,
             'client_id': self.auth_oauth_google_client_id,
         })