getting realm from carbon context

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@180799 a5903396-d722-0410-b921-86c7d4935375
using new jettison version 1.3.4

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@180802 a5903396-d722-0410-b921-86c7d4935375