refactoring do_openstack_upgrade to accept configs argument, bringing it in line with the other openstack charms

actions/openstack_upgrade.py

@@ -23,7 +23,7 @@ def openstack_upgrade():
     code to run, otherwise a full service level upgrade will fire
     on config-changed."""
 
-    if (do_action_openstack_upgrade('nova_compute-common',
+    if (do_action_openstack_upgrade('nova-common',
                                     do_openstack_upgrade,
                                     CONFIGS)):
         config_changed()

hooks/nova_compute_hooks.py

@@ -108,7 +108,7 @@ def config_changed():
             git_install(config('openstack-origin-git'))
     elif not config('action-managed-upgrade'):
         if openstack_upgrade_available('nova-common'):
-            CONFIGS = do_openstack_upgrade()
+            do_openstack_upgrade(CONFIGS)
 
     sysctl_dict = config('sysctl')
     if sysctl_dict:

hooks/nova_compute_utils.py

@@ -523,7 +523,7 @@ def import_authorized_keys(user='root', prefix=None):
             _keys.write('{}\n'.format(authorized_keys[index]))
 
 
-def do_openstack_upgrade():
+def do_openstack_upgrade(configs):
     # NOTE(jamespage) horrible hack to make utils forget a cached value
     import charmhelpers.contrib.openstack.utils as utils
     utils.os_rel = None
@@ -543,10 +543,8 @@ def do_openstack_upgrade():
     apt_install(determine_packages(), fatal=True)
 
     # Regenerate configs in full for new release
-    configs = register_configs()
     configs.write_all()
     [service_restart(s) for s in services()]
-    return configs
 
 
 def import_keystone_ca_cert():