igw: enable and start rbd-target-api

igw: enable and start rbd-target-api

The commit:

commit 1164cdc002cccb9dc1c6f10fb6b4370eafda3c4b
Author: Guillaume Abrioux <gabrioux@redhat.com>
Date:   Thu Aug 2 11:58:47 2018 +0200

    iscsigw: install ceph-iscsi-cli package

installs the cli package but does not start and enable the
rbd-target-api daemon needed for gwcli to communicate with the igw
nodes. This patch just enables and starts it for the non-container
setup. The container setup is already doing this.

This fixes bz https://bugzilla.redhat.com/show_bug.cgi?id=1613963

Signed-off-by: Mike Christie <mchristi@redhat.com>