cyclades: Fix bug in IP pools migration

Since the size of IP pools is not automatically computed by the size
of corresponding subnet, the data migration must add sizes to all
existing IP pools.

snf-cyclades-app/synnefo/db/migrations/0077_migrate_networks_to_subnets.py

@@ -3,6 +3,7 @@ import datetime
 from south.db import db
 from south.v2 import DataMigration
 from django.db import models
+import ipaddr
 
 class Migration(DataMigration):
 
@@ -18,9 +19,12 @@ class Migration(DataMigration):
                                                    dhcp=network.dhcp,
                                                    deleted=network.deleted)
                 ip_pool = network.pool
+                if ip_pool is None:
+                    ip_pool = IPPoolTable
                 ip_pool.subnet = subnet
                 ip_pool.base = subnet.cidr
                 ip_pool.offset = 0
+                ip_pool.size = ipaddr.IPNetwork(network.subnet).numhosts
                 ip_pool.save()
 
             if network.subnet6: