Bug 132786 Value2 should be cleaned after convert operator from between to equal in highlight rule.
Description: Value2 should be cleaned after convert operator from between to equal in highlight rule. Steps to reproduce: 1. Insert a data. 2. Set highlight rule in Property Editor. 2 between 1 and 3, color blue. 3. Save the report 4. Modify highlight rule, change to 1 equal 1, color blue. 5. Save the report, see generated xml source. Expected result: In xml source, value2 should be cleaned in highlight expression. Actual result: In xml source, value1 is 1 and value2 is 3.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/HighlightRuleHandle.java
* Returns the value2 of the highlight rule. Value2 is the value for simple
	 * conditions with the operators: between, not between.
	 * 
	 * @return the value2 as a string
	 */
	public String getValue2( )
	{
		return getStringProperty( HighlightRule.VALUE2_MEMBER );
	}
	/**
	 * gets the expression for this highlight rule.
	 * 
	 * @return the expression value
	 */
	public String getTestExpression( )
	{
		return getStringProperty( HighlightRule.TEST_EXPR_MEMBER );
	}
	/**
	 * sets the test expression for this hilghtlight rule.
	 * 
	 * @param expression
	 * 				the expression  
	 */
	
	public void setTestExpression( String expression ) 
	{
		setPropertySilently( HighlightRule.TEST_EXPR_MEMBER, expression );
	}
	/**