Description of problem:
Sometimes, some apply errata fails with message "Error while executing packages action: None".


Version-Release number of selected component (if applicable):
rhn-client-tools-0.4.20-77.el5


How reproducible:
rarely


Steps to Reproduce:
1. Schedule bunch of errata applications through WebUI
2. Run `rhn_check -vv` on the client


Actual results:
D: check_action {'action': "<?xml version='1.0'?>\n<methodCall>\n<methodName>errata.update</methodName>\n<params>\n<param>\n<value><array><data>\n<value><int>704</int></value>\n</data></array></value>\n</param>\n</params>\n</methodCall>\n", 'version': 2, 'id': 163}
updateLoginInfo() login info
D: login(forceUpdate=True) invoked
logging into up2date server
D: writeCachedLogin() invoked
D: Wrote pickled loginInfo at  1346284460.44  with expiration of  1346288060.44  seconds.
successfully retrieved authentication token from up2date server
D: logininfo: {'X-RHN-Server-Id': 1000010011, 'X-RHN-Auth-Server-Time': '1346284460.43', 'X-RHN-Auth': 'KyDuT3X2EAazyIEt5RaAhA==', 'X-RHN-Auth-Channels': [['parent-uuxrr', '20120829180522', '1', '1'], ['child-of-parent-uuxrr', '20120829180532', '0', '1']], 'X-RHN-Auth-User-Id': '', 'X-RHN-Auth-Expire-Offset': '3600.0'}
D: handle_action {'action': "<?xml version='1.0'?>\n<methodCall>\n<methodName>errata.update</methodName>\n<params>\n<param>\n<value><array><data>\n<value><int>704</int></value>\n</data></array></value>\n</param>\n</params>\n</methodCall>\n", 'version': 2, 'id': 163}
D: handle_action actionid = 163, version = 2
D: do_call errata.update ([704],) {'cache_only': None}
Loaded plugins: product-id, rhnplugin
D: Called update [['test-arch-uuxrr-1-InParent', '0.2', '2', '', 'i386']]
D: Sending back response ((6,), 'Error while executing packages action: None', {})

Please note that "None" which is strange.


Expected results:
It should work or provide better error message