Fixed Statement.cancel() causes NullPointerException if underlying connection has been closed due to server failure. (Bug#20650)

Added configuration option noAccessToProcedureBodies which will cause the driver to create basic parameter metadata for CallableStatements when the user does not have access to procedure bodies via SHOW CREATE PROCEDURE or selecting from mysql.proc instead of throwing an exception. The default value for this option is false

If the connection to the server has been closed due to a server failure, then the cleanup process will call Statement.cancel(), triggering a NullPointerException, even though there is no active connection. (Bug#20650)