Enforce correct choice for [DEFAULT] enabled_ssl_apis

The [DEFAULT] enabled_ssl_apis option is supposed to contain the subset
(or the same set) of the [DEFULT] enabled_apis option.

Because we accept only the correct values for enabled_apis, we can do
the same for enabled_ssl_apis. This would allow users to notice any
wrong values which were ignored previously.

Change-Id: Ibba8f3ea307df3e81e18c3a75361e27a0f52701d

Author: kajinamit

nova/conf/service.py

@@ -86,6 +86,8 @@
                 default=['osapi_compute', 'metadata'],
                 help="List of APIs to be enabled by default."),
     cfg.ListOpt('enabled_ssl_apis',
+                item_type=cfg.types.String(choices=['osapi_compute',
+                                                    'metadata']),
                 default=[],
                 help="""
 List of APIs with enabled SSL.