charm-helpers sync.

This sync is needed to bring in 2 fixes:

- python 3.10 (collections.abc.Iterable).
- Handle NoNameservers exception in ns_query().

Change-Id: I0b965b47b814e99d484682d7c90dcd60dd810ae7

charmhelpers/contrib/network/ip.py

@@ -467,7 +467,7 @@ def ns_query(address):
 
     try:
         answers = dns.resolver.query(address, rtype)
-    except dns.resolver.NXDOMAIN:
+    except (dns.resolver.NXDOMAIN, dns.resolver.NoNameservers):
         return None
 
     if answers:

charmhelpers/core/services/base.py

@@ -15,7 +15,8 @@
 import os
 import json
 import inspect
-from collections import Iterable, OrderedDict
+from collections import OrderedDict
+from collections.abc import Iterable
 
 from charmhelpers.core import host
 from charmhelpers.core import hookenv