Bug 146976 Save state of the report not correct.
Reproduce: 1) New a library "lib1", add a label "label1" 2) Publish "lib1" 3) New a report "report1", use "lib1" 4) Drag "lib1.label1" into "report1" 5) Go back to "lib1", drop "label1", save and publish again. 6) Go to "report1", refresh the libaray explorer and design. 7) Save "report1" 8) Now, we go back to "lib1" 9) Undo the previous "delete command", "label1" is added back. 10) Save "lib1", and re-publish. 11) Go to "report1", refresh the libaray explorer and design. 12) Save "report1" At this stage, "report1" is saved, but the dirty indicator(*) still displayed in the left side of the report name. I am testing on build N20060613
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* Sets the UTF signature of this module file.
	 * 
	 * @param signature
	 *            the UTF signature of the module file.
	 */
	public void setUTFSignature( String signature )
	{
		this.signature = signature;
	}
	/**
	 * Gets the UTF signature of this module file.
	 * 
	 * @return the UTF signature of the module file.
	 */
	public String getUTFSignature( )
	{
		return signature;
	}
	/**
	 * Returns the number of slots of the module. For the library and the report
	 * design, this number is different.
	 * 
	 * @return the number of slots of the module
	 */
	protected abstract int getSlotCount( );
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.core.DesignElement#getSlot(int)
	 */