Correctly handle EmptyModlist exception in pwpolicy2-mod.

EmptyModlist exception was generated by pwpolicy2-mod when modifying
policy priority only. It was because the priority attribute is stored
outside of the policy entry (in a CoS entry) and there was nothing
left to be changed in the policy entry.

This patch uses the new exception callbacks in baseldap.py classes
to catch the EmptyModlist exception and checks if there was really
nothing to be modified before reraising the exception.

ipalib/plugins/pwpolicy2.py

@@ -276,12 +276,19 @@ class pwpolicy2_mod(LDAPUpdate):
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
         if not options.get('raw', False):
             if options.get('cospriority') is not None:
-                entry_attrs['cospriority'] = [unicode(options['copriority'])]
+                entry_attrs['cospriority'] = [unicode(options['cospriority'])]
             if keys[-1] is None:
                 entry_attrs['cn'] = GLOBAL_POLICY_NAME
         self.obj.convert_time_for_output(entry_attrs, **options)
         return dn
 
+    def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
+        if isinstance(exc, errors.EmptyModlist):
+            entry_attrs = call_args[1]
+            if not entry_attrs and 'cospriority' in options:
+                return
+        raise exc
+
 api.register(pwpolicy2_mod)
 
 
@@ -340,12 +347,13 @@ class pwpolicy2_find(LDAPSearch):
                 except errors.NotFound:
                     pass
                 self.obj.convert_time_for_output(e[1], **options)
-        global_entry = self.api.Command.pwpolicy2_show(
-            all=options.get('all', False), raw=options.get('raw', False)
-        )['result']
-        dn = global_entry['dn']
-        del global_entry['dn']
-        entries.insert(0, (dn, global_entry))
+        if not args[-1]:
+            global_entry = self.api.Command.pwpolicy2_show(
+                all=options.get('all', False), raw=options.get('raw', False)
+            )['result']
+            dn = global_entry['dn']
+            del global_entry['dn']
+            entries.insert(0, (dn, global_entry))
 
 api.register(pwpolicy2_find)