Description of problem:
https://access.redhat.com/documentation/en/red-hat-openstack-platform/9/paged/instances-and-images-guide/chapter-1-image-service says:

1.2.1.2.1. Create a Red Hat Enterprise Linux 7 Image
...
9.  Edit the /etc/cloud/cloud.cfg configuration file and under cloud_init_modules add:

- resolv-conf

The resolv-conf option automatically configures the resolv.conf when an instance boots for the first time. This file contains information related to the instance such as nameservers, domain and other options.
"

But when checking cloud-init logs with this change we see:

/var/log/cloud-init-output.log:2016-11-03 12:22:36,796 - importer.py[DEBUG]: Looking for modules ['cc_resolv_conf', 'cloudinit.config.cc_resolv_conf'] that have attributes ['handle']
/var/log/cloud-init-output.log:2016-11-03 12:22:36,796 - importer.py[DEBUG]: Failed at attempted import of 'cc_resolv_conf' due to: No module named cc_resolv_conf
/var/log/cloud-init-output.log:2016-11-03 12:22:36,834 - importer.py[DEBUG]: Found cc_resolv_conf with attributes ['handle'] in ['cloudinit.config.cc_resolv_conf']
/var/log/cloud-init-output.log:2016-11-03 12:22:37,628 - util.py[DEBUG]: Writing to /var/lib/cloud/instances/iid-datasource-none/sem/config_resolv_conf - wb: [420] 19 bytes
/var/log/cloud-init-output.log:2016-11-03 12:22:37,633 - helpers.py[DEBUG]: Running config-resolv-conf using lock (<FileLock using file '/var/lib/cloud/instances/iid-datasource-none/sem/config_resolv_conf'>)
/var/log/cloud-init-output.log:2016-11-03 12:22:37,633 - cc_resolv_conf.py[DEBUG]: Skipping module named resolv-conf, no 'manage_resolv_conf' key in configuration

Also, it should be explained when this is needed if DHCP is already in use.