private static void deleteNamespace(MasterProcedureEnv env, String namespaceName)
    throws IOException {
    getTableNamespaceManager(env).deleteNamespace(namespaceName);
  }
delete the row from the ns family in meta table.
@param env           MasterProcedureEnv
@param namespaceName name of the namespace in string format
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DeleteNamespaceProcedure.java