Failed connect to 0.0.0.0:8091 while running setupNetConfig curl after upgrading from 5.5.0 to 5.5.3/6.0.1

Setup on CentOS 7 Vagrant : 2 Node cluster, IPv6 only Machines

1. Install build 5.5.0-2958
2. Cluster is up in IPv4 mode, stop the service and make static_config changes to start in IPv6
3. Remove file /opt/couchbase/var/lib/couchbase/config/config.dat
4. Start back the server, both the nodes are up in IPv6
5. Load sample buckets and wait for buckets to load
6. Disable auto failover and stop the server's
7. Do an offline upgrade using rpm -Uvh to EE build 5.5.3-4021 or 6.0.1-1967
8. As per the new changes the ipv6 entry is removed from static_config and user has to run the curl
9. When I run the curl we get ‘Failed connect to 0.0.0.0:8091; Connection refused 

               curl -v -u Administrator:password -d 'afamily=ipv6' http://0.0.0.0:8091/node/controller/setupNetConfig

1. [root@localhost ~]# netstat -nltp | grep beam

      tcp        0      0 0.0.0.0:21100           0.0.0.0:*               LISTEN      7410/beam.smp

If we manually change the entry in dist_cfg from inet_tcp to inet6_tcp and then restart the server the service is back on IPv6.