osad service startup gives "SSL3_GET_SERVER_CERTIFICATE (certificate verify failed)" error

Issue

• on a client registered with RHN Satellite, the osad service is failing to start up, with the following error:

[root@client ~]# service osad restart
Shutting down osad:                                        [FAILED]
Starting osad: Traceback caught:
Traceback (most recent call last):
  File "/usr/share/rhn/osad/jabber_lib.py", line 620, in connect
    ssl.do_handshake()
Error: [('SSL routines', 'SSL3_GET_SERVER_CERTIFICATE', 'certificate verify failed')]
[FAILED]