PXB-3240: Fix keyring/rolback.sh test failure.

The test expects only a table to be encrypted but we have undo
and redo also encrypted because of configuration
MYSQLD_EXTRA_MY_CNF_OPTS in configure_server_with_component
This causes undo and redo to be encrypted.

Then if backup is taken without keyring component, it fails as
undo and redo are encrypted.

Fix:
----
Ensure that redo,undo and binlog are not encrypted. Only one encrypted
table and rollback on this table. Lack of component, shouldn't fail the
prepare

storage/innobase/xtrabackup/test/suites/keyring/rollback.sh

@@ -69,6 +69,10 @@ cp ${keyring_component_cnf} $mysql_datadir
 start_server
 verify_db_state test
 
+# Reconfigure without innodb_undo_log_encrypt/redo_log_encrypt/binlog_encrypt
+MYSQLD_EXTRA_MY_CNF_OPTS=""
+configure_server_with_component
+
 vlog "Test 2: No rollback on encrypted table. Lack of keyring shouldn't fail the prepare"
 
 vlog "Backup"