Reverting r174945: Pluggable Authenticators

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@176685 a5903396-d722-0410-b921-86c7d4935375
Reverting r174944: Pluggable Authenticators

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@176686 a5903396-d722-0410-b921-86c7d4935375