Description of problem:

The validation of server certificate is not supported on rhel5. There is an appropriate error reported by the client, which is correct:
    raise SSLError("This version of Python does not support verification of the peer's certificate.")

But the 'SSLError' class is not known, so the client ends with a NameError:
NameError: global name 'SSLError' is not defined

See additional info for details.

Version-Release number of selected component (if applicable):
python-qpid-0.18-4

How reproducible:
100%

Steps to Reproduce:
1. setup ssl broker
2. connect to the broker using python client, request server certificate validation by supplying ssl_trustfile connection option
3. NameError

Actual results:
NameError on server certificate validation attempt

Expected results:
Appropriate exception is displayed to the user

Additional info:

* qc2_drain.py is a modified version of python drain example that supports connection options

# ~/qc2_drain.py -b amqps://$(hostname):5671 "amq.direct/test" --connection-options "{ssl_certfile:/var/lib/qpidd/qpid_nss_db/client.pem, ssl_trustfile:/var/lib/qpidd/qpid_nss_db/rootca.crt}"
Traceback (most recent call last):
  File "/root/qc2_drain.py", line 171, in ?
    conn.open()
  File "<string>", line 6, in open
  File "/usr/lib/python2.4/site-packages/qpid/messaging/endpoints.py", line 261, in open
    self.attach()
  File "<string>", line 6, in attach
  File "/usr/lib/python2.4/site-packages/qpid/messaging/endpoints.py", line 279, in attach
    self._ewait(lambda: self._transport_connected and not self._unlinked())
  File "/usr/lib/python2.4/site-packages/qpid/messaging/endpoints.py", line 214, in _ewait
    self.check_error()
  File "/usr/lib/python2.4/site-packages/qpid/messaging/endpoints.py", line 207, in check_error
    raise self.error
qpid.messaging.exceptions.InternalError: Traceback (most recent call last):
  File "/usr/lib/python2.4/site-packages/qpid/messaging/driver.py", line 509, in dispatch
    self.connect()
  File "/usr/lib/python2.4/site-packages/qpid/messaging/driver.py", line 533, in connect
    self._transport = trans(self.connection, host, port)
  File "/usr/lib/python2.4/site-packages/qpid/messaging/transports.py", line 79, in __init__
    raise SSLError("This version of Python does not support verification of the peer's certificate.")
NameError: global name 'SSLError' is not defined