addons: address: fix processing of 'preferred-lifetime' attribute

Ticket: CM-8773
Reviewed By: CCR-4079
Testing Done:Yes, with following cofiguration

auto swp1
iface swp1
	address 71.12.21.43
	address 2001:620:5ca1:160::47
	preferred-lifetime 30

Fix for this is, a small update in address.py method '_inet_address_convert_to_cidr'
where there is a check for different addres attributes.

addons/address.py

@@ -147,7 +147,7 @@ class address(moduleBase):
                         'preferred-lifetime']:
                     aval = ifaceobj.get_attr_value_n(a, addr_index)
                     if aval:
-                        attrs['broadcast'] = aval
+                        attrs[a] = aval
 
                 if attrs:
                     newaddr_attrs[newaddr]= attrs