removing unused TenantPersister

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@179708 a5903396-d722-0410-b921-86c7d4935375
introducing addSkeletonTenant

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@179709 a5903396-d722-0410-b921-86c7d4935375