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
* <li><code>DesignChoiceConstants.STRING_FORMAT_TYPE_PHONE_NUMBER</code>
	 * <li>
	 * <code>DesignChoiceConstants.STRING_FORMAT_TYPE_SOCIAL_SECURITY_NUMBER</code>
	 * </ul>
	 * 
	 * @param category
	 *            the category of a string format
	 * @throws SemanticException
	 *             if <code>category</code> is not one of the above values.
	 */
	public void setStringFormatCategory( String category )
			throws SemanticException
	{
		setFormatValue( HighlightRule.STRING_FORMAT_MEMBER,
				FormatValue.CATEGORY_MEMBER, category );
	}
	/**
	 * Returns the pattern of a number format for a highlight rule.
	 * 
	 * @return the pattern of a number format
	 */
	public String getNumberFormat( )
	{
		Object value = getProperty( HighlightRule.NUMBER_FORMAT_MEMBER );
		if ( value == null )
			return null;
		assert value instanceof NumberFormatValue;
		return ( (NumberFormatValue) value ).getPattern( );
	}
	/**