Handle unsecure cluster convert to secure cluster for SCM

In SCM sub-ca certs are setup during init, if a cluster is converted to secure later, in else part of the scmInit, we need to initialize security.

OM handled this scenario, SCM also needs a similar fix.
https://github.com/apache/ozone/blob/master/hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OzoneManager.java#L963