Ignore exceptions getting FloatingIP dependencies

When calculating the dependencies for a FloatingIP resource, we make
REST calls to Neutron. If this call fails then we will stop looking for
implicit dependencies for that resource. (Prior to the fix for bug
1554625, it would have broken the stack altogether.)

This change ignores any errors that occur while making the client call,
so that any other implicit dependencies can potentially still be
discovered.

Change-Id: Ic9220041e7bf85b4388ad283082833cfbdb6c76a
Story: #1442121
Task: 16622

heat/engine/resources/openstack/neutron/floatingip.py

@@ -12,6 +12,8 @@
 #    under the License.
 import six
 
+from oslo_log import log as logging
+
 from heat.common import exception
 from heat.common.i18n import _
 from heat.engine import attributes
@@ -23,6 +25,8 @@ from heat.engine.resources.openstack.neutron import router
 from heat.engine import support
 from heat.engine import translation
 
+LOG = logging.getLogger(__name__)
+
 
 class FloatingIP(neutron.NeutronResource):
     """A resource for managing Neutron floating ips.
@@ -217,8 +221,14 @@ class FloatingIP(neutron.NeutronResource):
                 p_net = (resource.properties.get(port.Port.NETWORK) or
                          resource.properties.get(port.Port.NETWORK_ID))
                 if p_net:
-                    network = self.client().show_network(p_net)['network']
-                    return subnet in network['subnets']
+                    try:
+                        network = self.client().show_network(p_net)['network']
+                        return subnet in network['subnets']
+                    except Exception as exc:
+                        LOG.info("Ignoring Neutron error while "
+                                 "getting FloatingIP dependencies: %s",
+                                 six.text_type(exc))
+                        return False
             else:
                 for fixed_ip in resource.properties.get(
                         port.Port.FIXED_IPS):