Fixes nova-manage fixed list with deleted networks

The fix addresses the bug reported in bug 1025827
currently command 'nova-manage fixed list' will return
'Command failed.' message when there is no network defined or
all networks have been deleted or even when a network gets
deleted, then a new network gets created. In all these cases,
the command produces the 'Command failed.' error message which
does not really tell what went wrong. This fix will produce
'No fixed IP found' in these conditions.
changes made for globalization.
changes made for based on the comments for patchset 7.

Change-Id: I3c2e9bf3fa3c748e680c1df27d243a648ed47cf5

bin/nova-manage

@@ -282,24 +282,43 @@ class FixedIpCommands(object):
                                               _('IP address'),
                                               _('hostname'),
                                               _('host'))
+
+        all_networks = {}
+        try:
+            # use network_get_all to retrieve all existing networks
+            # this is to ensure that IPs associated with deleted networks
+            # will not throw exceptions.
+            for network in db.network_get_all(context.get_admin_context()):
+                all_networks[network.id] = network
+        except exception.NoNetworksFound:
+            # do not have any networks, so even if there are IPs, these
+            # IPs should have been deleted ones, so return.
+            print _('No fixed IP found.')
+            return
+
+        has_ip = False
         for fixed_ip in fixed_ips:
             hostname = None
             host = None
             mac_address = None
-            network = db.network_get(context.get_admin_context(),
-                                     fixed_ip['network_id'])
-            if fixed_ip['instance_id']:
-                instance = instances_by_id.get(fixed_ip['instance_id'])
-                if instance:
-                    hostname = instance['hostname']
-                    host = instance['host']
-                else:
-                    print ('WARNING: fixed ip %s allocated to missing'
-                           ' instance' % str(fixed_ip['address']))
-            print "%-18s\t%-15s\t%-15s\t%s" % (
-                    network['cidr'],
-                    fixed_ip['address'],
-                    hostname, host)
+            network = all_networks.get(fixed_ip['network_id'])
+            if network:
+                has_ip = True
+                if fixed_ip['instance_id']:
+                    instance = instances_by_id.get(fixed_ip['instance_id'])
+                    if instance:
+                        hostname = instance['hostname']
+                        host = instance['host']
+                    else:
+                        print _('WARNING: fixed ip %s allocated to missing'
+                                ' instance') % str(fixed_ip['address'])
+                print "%-18s\t%-15s\t%-15s\t%s" % (
+                        network['cidr'],
+                        fixed_ip['address'],
+                        hostname, host)
+
+        if not has_ip:
+            print _('No fixed IP found.')
 
     @args('--address', dest="address", metavar='<ip address>',
           help='IP address')