format: Stabilise partition addresses

Depending on the netifaces version the netmask can come with or without
lenght prefix, so support both cases and consider netmask with prefix
as equal to without prefix.

The only result will be update of the netmask in the computer XML file.

slapos/format.py

@@ -1178,11 +1178,20 @@ class Interface(object):
     address_dict = interface_addr_list[0]
 
     if addr is not None:
-      dict_addr_netmask = dict(addr=addr, netmask=netmask)
-      if dict_addr_netmask in interface_addr_list or \
-         (tap and dict_addr_netmask in self.getGlobalScopeAddressList(tap=tap)):
-        # confirmed to be configured
-        return dict_addr_netmask
+      # support netifaces which returns netmask and netmask/len
+      # will result with updating the computer XML netmask only
+      # to follow the change of netmask representation in netifaces
+      if '/' in netmask:
+        dict_addr_netmask_with_len = dict(addr=addr, netmask=netmask)
+        dict_addr_netmask_without_len = dict(addr=addr, netmask=netmask.split('/')[0])
+      else:
+        dict_addr_netmask_without_len = dict(addr=addr, netmask=netmask)
+        dict_addr_netmask_with_len = dict(addr=addr, netmask='%s/%s' % (netmask, lenNetmaskIpv6(netmask)))
+      for dict_addr_netmask in [dict_addr_netmask_with_len, dict_addr_netmask_without_len]:
+        if dict_addr_netmask in interface_addr_list or \
+           (tap and dict_addr_netmask in self.getGlobalScopeAddressList(tap=tap)):
+          # confirmed to be configured
+          return dict_addr_netmask
       if netmask == address_dict['netmask'] or \
          (tap and lenNetmaskIpv6(netmask) == 128):
         # same netmask, so there is a chance to add good one