Enable swift payload upgrades for wallaby+

Sync charm-helpers to pick up fix for openstack_upgrade_available
that enables successful payload upgrades. This will need backporting
to stable/wallaby.

https://github.com/openstack-charmers/zaza/pull/619
Closes-Bug: #2040606
Change-Id: Ib5f446d617c11c9c9046c33335c1099b21b5166e

charmhelpers/contrib/openstack/utils.py

@@ -416,17 +416,6 @@ def get_os_version_codename(codename, version_map=OPENSTACK_CODENAMES,
     error_out(e)
 
 
-def get_os_version_codename_swift(codename):
-    '''Determine OpenStack version number of swift from codename.'''
-    # for k, v in six.iteritems(SWIFT_CODENAMES):
-    for k, v in SWIFT_CODENAMES.items():
-        if k == codename:
-            return v[-1]
-    e = 'Could not derive swift version for '\
-        'codename: %s' % codename
-    error_out(e)
-
-
 def get_swift_codename(version):
     '''Determine OpenStack codename that corresponds to swift version.'''
     codenames = [k for k, v in SWIFT_CODENAMES.items() if version in v]
@@ -585,7 +574,6 @@ def get_installed_os_version():
     return openstack_release().get('OPENSTACK_CODENAME')
 
 
-@cached
 def openstack_release():
     """Return /etc/os-release in a dict."""
     d = {}
@@ -847,14 +835,10 @@ def openstack_upgrade_available(package):
     if not cur_vers:
         # The package has not been installed yet do not attempt upgrade
         return False
-    if "swift" in package:
-        codename = get_os_codename_install_source(src)
-        avail_vers = get_os_version_codename_swift(codename)
-    else:
-        try:
-            avail_vers = get_os_version_install_source(src)
-        except Exception:
-            avail_vers = cur_vers
+    try:
+        avail_vers = get_os_version_install_source(src)
+    except Exception:
+        avail_vers = cur_vers
     apt.init()
     return apt.version_compare(avail_vers, cur_vers) >= 1