Merge pull request #90 from mansam/fix-network-port-subnet-collection

Old Refresh: Don't error out if a port refers to an unknown subnet.
(cherry picked from commit c7c8332e68633188b220ee8948963c254506ce29)

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1564264

app/models/manageiq/providers/openstack/network_manager/refresh_parser.rb

@@ -208,7 +208,7 @@ def find_device_object(network_port)
         subnet_id               = network_port.fixed_ips.try(:first).try(:[], "subnet_id")
         network_router          = @data_index.fetch_path(:network_routers, network_port.device_id)
         subnet                  = @data_index.fetch_path(:cloud_subnets, subnet_id)
-        subnet[:network_router] = network_router
+        subnet[:network_router] = network_router unless subnet.nil?
       end
       # Returning nil for non VM port, we don't want to store those as ports
       nil