If key_instantiate_and_link() were to fail (which fortunately isn't
possible currently), the call to key_revoke(authkey) would crash with a
NULL pointer dereference in request_key_auth_revoke() because the key
has not yet been instantiated.
Fix this by removing the call to key_revoke().  key_put() is sufficient,
as it's not possible for an uninstantiated authkey to have been used for
anything yet.
Fixes: b5f545c880a2 ("[PATCH] keys: Permit running process to instantiate keys")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
        return authkey;
 
 error_put_authkey:
-       key_revoke(authkey);
        key_put(authkey);
 error_free_rka:
        free_request_key_auth(rka);