MB-34161 Add comment on when otpNode should be used

Change-Id: I1a7d876f762b72f7691250d9a510a95fa8301fe5
Reviewed-on: http://review.couchbase.org/113022
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Carlos Gonzalez <carlos.gonzalez@couchbase.com>

Author: mcpaddy

cluster_manager.py

@@ -639,6 +639,8 @@ def rebalance_status(self):
 
         return rv, None
 
+    # otpNode should only be printed out or handed back to ns_server
+    # It should never be used to create a connection to a node
     def _get_otps_names(self, eject_nodes=[], failover_nodes=[], readd_nodes=[]):
         result, errors = self.pools('default')
         if errors: