schema/defs-linux: Fix inconsistencies with seccomp notify

Commit "Add Seccomp Notify support"
(58798e7) just added
SECCOMP_FILTER_FLAG_NEW_LISTENER to the schema and not to the list of
flags in config-linux.md. However, it was a mistake to add them to the
schema, as the user will never really need to specify that flag.

Signed-off-by: Rodrigo Campos <rodrigo@kinvolk.io>

Author: rata

schema/defs-linux.json

@@ -70,8 +70,7 @@
             "enum": [
                 "SECCOMP_FILTER_FLAG_TSYNC",
                 "SECCOMP_FILTER_FLAG_LOG",
-                "SECCOMP_FILTER_FLAG_SPEC_ALLOW",
-                "SECCOMP_FILTER_FLAG_NEW_LISTENER"
+                "SECCOMP_FILTER_FLAG_SPEC_ALLOW"
             ]
         },
         "SeccompOperators": {