fixing caching failures

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@179538 a5903396-d722-0410-b921-86c7d4935375
adding app cache constant

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@179539 a5903396-d722-0410-b921-86c7d4935375