Fix for issue SS-324 pagination selection of page in hdfs ui and items per page selection

pagination modification in std_view_content.jsp 
Selected page can be seen
A combo box for items per page was added
Make it a habit to check the constant against the variable when doing the above comparison. Always helpful in getting rid of that additional null check which is redundant. For example, the above "if" statement can be reconstructed as << if ("false".equals(isFolder)) >>. Not only that if the string "false" is used within multiple places, you can consider declaring it as a constant and using it too.