I think this is a regression added to ceph-iscsi-config/rbd-target-gw. Looking into it.
The logs show it at least attempted to add the portal: 2017-09-27 18:36:04,624 [ DEBUG] - (Gateway.create_tpg) Added tpg for portal ip 10.70.39.14 2017-09-27 18:36:04,624 [ DEBUG] - (Gateway.create_tpg) Added tpg for portal ip 10.70.39.14 is enabled 2017-09-27 18:36:04,624 [ INFO] - (Gateway.create_tpg) created TPG '3' for target iqn 'iqn.2003-01.com.redhat.iscsi-gw:ceph'
Verified on ceph-iscsi-config-2.3-9.el7cp.noarch
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2017:3387