[ActionManager] modify the comment message.
[DBClientAction] change variable name, and nototion of value.

const static guint ACTION_DELETE_DEFAULT_INTERVAL = 3600000;
-> const static guint DEFAULT_ACTION_DELETE_INTERVAL = 3600 * 1000;
[DBClientAction] Add try/catch process.

Receive an exception that DBCLIENT_TRANSACTION_END has sent
when recive the exception , the process is continues.