Fixes #2222: IP addresses created via the available-ips API endpoint …

…should have the same mask as their parent prefix (not /32)

netbox/ipam/api/views.py

@@ -196,8 +196,9 @@ def available_ips(self, request, pk=None):
 
             # Assign addresses from the list of available IPs and copy VRF assignment from the parent prefix
             available_ips = iter(available_ips)
+            prefix_length = prefix.prefix.prefixlen
             for requested_ip in requested_ips:
-                requested_ip['address'] = next(available_ips)
+                requested_ip['address'] = '{}/{}'.format(next(available_ips), prefix_length)
                 requested_ip['vrf'] = prefix.vrf.pk if prefix.vrf else None
 
             # Initialize the serializer with a list or a single object depending on what was requested