core: smack-setup: Actually allow for succesfully loading CIPSO policy

The line under the last switch statement  *loaded_policy = true;
would never be executed. As all switch cases return 0. Thus the
policy would never be marked as loaded.

Found with Coverity. Fixes: CID#1237785

src/core/smack-setup.c

@@ -158,7 +158,7 @@ int smack_setup(bool *loaded_policy) {
                 return 0;
         case 0:
                 log_info("Successfully loaded Smack/CIPSO policies.");
-                return 0;
+                break;
         default:
                 log_warning("Failed to load Smack/CIPSO access rules: %s, ignoring.",
                             strerror(abs(r)));