Documentation fix for admin_address

This is _not_ an email address but actually a host. Caught the typo
trying to use this module.

Change-Id: I54709ecd0bf9efaeb00f97209c78205ef48a4c45
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>

README.md

@@ -83,8 +83,9 @@ class { 'glance::db::mysql':
 ```puppet
 class { 'glance::keystone::auth':
   password         => '12345'
+  email            => 'glance@example.com',
   public_address   => '172.17.0.3',
-  admin_address    => 'admin@example.com',
+  admin_address    => '172.17.0.3',
   internal_address => '172.17.1.3',
   region           => 'example-west-1',
 }