Bug 144106 [Regression]Parameter request page pops up twice while running the report with cascading parameter
Steps to reproduce: 1.Add a cascading parameter group with a parameter 2.Preview Expected result: The parameter request page just pops up once for input value Actual result: The parameter request page pops up twice when inputting parameter value
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
{
					paramValueObj = ParameterValidationUtil.validate( parameter
							.getDataType( ), parameter.getPattern( ),
							paramValueObj.toString( ), locale );
					params.put( paramName, paramValueObj );
				}
				catch ( ValidationValueException e )
				{
					
					if ( ParameterAccessor.SERVLET_PATH_RUN
							.equalsIgnoreCase( request.getServletPath( ) ) )
					{
						this.exception = e;
						break;
					}
				}
			}
			else
			{
				params.put( paramName, null );
			}
		}
		return params;
	}
	/**
	 * get parameter object.
	 * 
	 * @param request
	 *            HttpServletRequest
	 * @param parameter