Lps 45608

The original issue happened because activities portlet and members activities portlet use same friendly mapper url, when user click RSS icon in members activites portlet, portal throw Princinple exception because following code:
checkResource(ownerLayoutRequest, portlet); (line 164 SecurityPortletContainerWrapper)

Portal pass a wrong portlet (activities) to checkResource method cause throw Princinple exception, the portlet should be members activities portlet

To fix this issue, I add new RSS handle class for members activities portlet and make them use individual friendly mapper url

For class MembersActivitiesPortlet, I copied the methods exportToRSS  getActivities and getRSS from class com.liferay.portlet.activities.action.RSSAction