Stop creating a keystone admin site

Keystone no longer has any special functionality hidden behind the admin
site. KEYSTONE_AUTH_URI which used to point to the admin site has long
ago been changed to be a copy of KEYSTONE_SERVICE_URI, which points to
the public site.

Drop all KEYSTONE_AUTH_* variables except KEYSTONE_AUTH_URI which may
still be in use in some plugins.

This also allows to finally drop the fixup_keystone() function.

Change-Id: I549f3cadc27d137e014241cdd47e90267859c848
diff --git a/stack.sh b/stack.sh
index 48f61fb..fc26e21 100755
--- a/stack.sh
+++ b/stack.sh
@@ -876,7 +876,7 @@
 install_keystonemiddleware
 
 if is_service_enabled keystone; then
-    if [ "$KEYSTONE_AUTH_HOST" == "$SERVICE_HOST" ]; then
+    if [ "$KEYSTONE_SERVICE_HOST" == "$SERVICE_HOST" ]; then
         stack_install_service keystone
         configure_keystone
     fi
@@ -1093,7 +1093,7 @@
 if is_service_enabled keystone; then
     echo_summary "Starting Keystone"
 
-    if [ "$KEYSTONE_AUTH_HOST" == "$SERVICE_HOST" ]; then
+    if [ "$KEYSTONE_SERVICE_HOST" == "$SERVICE_HOST" ]; then
         init_keystone
         start_keystone
         bootstrap_keystone