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

Documentation/dev-design.txt

diff --git a/Documentation/dev-design.txt b/Documentation/dev-design.txt
index fd53cac..0243a58 100644
--- a/Documentation/dev-design.txt
+++ b/Documentation/dev-design.txt
@@ -255,11 +255,7 @@
 
 Gerrit integrates with any OpenID provider for user authentication,
 making it easier for users to join a Gerrit site and manage their
-authentication credentials to it.  To make use of Google Accounts
-as an OpenID provider easier, Gerrit has a shorthand "Sign in with
-a Google Account" link on its sign-in screen.  Gerrit also supports
-a shorthand sign in link for Yahoo!.  Other providers may also be
-supported more directly in the future.
+authentication credentials to it.
 
 Site administrators may limit the range of OpenID providers to
 a subset of "reliable providers".  Users may continue to use