Bug 178164 Use IEngineTask.status constants and remove unnecessary status variables in EngineTask.
1)Remove following redundant variables in EngineTask used for status info. protected final int RUNNING_STATUS_START = 0; protected final int RUNNING_STATUS_RUNNING = 1; protected final int RUNNING_STATUS_STOP = 2; EngineTask already has access to constants declared in IEngineTask. Use those instead. 2)Remove the unused errorHandlingOption in EngineTask.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
* a reference to the report engine
	 */
	protected IReportEngine engine;
	/**
	 * Comment for <code>locale</code>
	 */
	protected Locale locale = Locale.getDefault( );
	/**
	 * the execution context
	 */
	protected ExecutionContext executionContext;
	/**
	 * task identifier. Could be used for logging
	 */
	protected int taskID;
	protected IReportRunnable runnable;
	/**
	 * options used to render the report design.
	 */
	protected IRenderOption renderOptions;
	/**
	 * emitter id
	 */
	protected String emitterID;
	
	/**
	 * does the parameter has been changed by the user.
	 */
	protected boolean parameterChanged = true;
	/**