cephadm-adopt: fix "Update the placement of radosgw hosts" task

networks was at the wrong level in the spec file. Failed with
"got an unexpected keyword argument 'networks'"

Signed-off-by: Teoman ONAY <tonay@ibm.com>

infrastructure-playbooks/cephadm-adopt.yml

@@ -943,7 +943,7 @@
             hosts:
               - {{ ansible_facts['nodename'] }}
           {% if rgw_subnet is defined %}
-            networks: "{{ rgw_subnet }}"
+          networks: "{{ rgw_subnet }}"
           {% endif %}
           spec:
             rgw_frontend_port: {{ radosgw_frontend_port }}