Fixing CARBON-13957. Added some constants.

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/kernel/trunk@175728 a5903396-d722-0410-b921-86c7d4935375
Fixing CARBON-13957. set serverConfig into the servlet context

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/kernel/trunk@175729 a5903396-d722-0410-b921-86c7d4935375