code refactoring

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@178059 a5903396-d722-0410-b921-86c7d4935375
Adding improvements to apimgt.interceptor.

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@178060 a5903396-d722-0410-b921-86c7d4935375