Update dirPagination.js
Update dirPagination.js

add watch on getItemsPerPage to make possible change itemsPerPage from scope.
```
row in rows | itemsPerPage: rowsPerPage
```
pkdevbox/angularUtils,Kerruba/angularUtils,humpy125/angularUtils,allanlb/angularUtils,michaelbromley/angularUtils,wpsmith/angularUtils,telesma/angularUtils,wesleyliu/angularUtils,wesleyliu/angularUtils,jlgrock/angularUtils,romelgomez/angularUtils,Git1111/angularUtils,allanlb/angularUtils,imakmgit/angularUtils,saike/angularUtils,michaelbromley/angularUtils,radhikagiri/angularUtils,phw/angularUtils,benoror/angularUtils,telesma/angularUtils,Kerruba/angularUtils,danlobo/angularUtils,noahxinhao/angularUtils,Git1111/angularUtils,dszmaj/angularUtils,radhikagiri/angularUtils,yshyee/angularUtils,tianhengzhou/angularUtils,narasingh/angularUtils,kzganesan/angularUtils,noahxinhao/angularUtils,danlobo/angularUtils,zzzzzyuzhang/angularUtils,tianhengzhou/angularUtils,benoror/angularUtils,narasingh/angularUtils,dszmaj/angularUtils,jlgrock/angularUtils,yshyee/angularUtils,alexkuttig/angularUtils,zzzzzyuzhang/angularUtils,romelgomez/angularUtils,saike/angularUtils,wpsmith/angularUtils,kzganesan/angularUtils,phw/angularUtils,pkdevbox/angularUtils,alexkuttig/angularUtils,imakmgit/angularUtils,humpy125/angularUtils