Add keystone VirtualHost for port 443 when USE_SSL is True

Add a VirtualHost that defines the necessary options for
enabling SSL. The existing keystone Apache configuration already
does all the location handling.

Change-Id: I836a471a7258f14f051d3dd8bdb428286b5a11aa
diff --git a/files/apache-keystone.template b/files/apache-keystone.template
index 8a4b0f0..249eaa5 100644
--- a/files/apache-keystone.template
+++ b/files/apache-keystone.template
@@ -34,6 +34,12 @@
     %SSLKEYFILE%
 </VirtualHost>
 
+%SSLLISTEN%<VirtualHost *:443>
+%SSLLISTEN%    %SSLENGINE%
+%SSLLISTEN%    %SSLCERTFILE%
+%SSLLISTEN%    %SSLKEYFILE%
+%SSLLISTEN%</VirtualHost>
+
 Alias /identity %KEYSTONE_BIN%/keystone-wsgi-public
 <Location /identity>
     SetHandler wsgi-script