OpenID: Remove support for Yahoo! OpenID provider

Yahoo! discontinued support for OpenID provider: [1]

"OpenID2 will be EOLed on 6/30/20"

[1] https://developer.yahoo.com/oauth2/guide/OpenID2

Bug: Issue 13140
Bug: Issue 14330
Change-Id: I49a3adf5a331f119af8393d2403e98a7b3dcd654

Documentation/config-sso.txt

diff --git a/Documentation/config-sso.txt b/Documentation/config-sso.txt
index 6f3a32d..88de85e 100644
--- a/Documentation/config-sso.txt
+++ b/Documentation/config-sso.txt
@@ -43,9 +43,9 @@
 * `http://` -- trust all OpenID providers using the HTTP protocol
 * `https://` -- trust all OpenID providers using the HTTPS protocol
 
-To trust only Yahoo!:
+To trust only Launchpad:
 ----
-  git config --file $site_path/etc/gerrit.config auth.trustedOpenID https://me.yahoo.com
+  git config --file $site_path/etc/gerrit.config auth.trustedOpenID https://login.launchpad.net/+openid
 ----
 
 === Database Schema