When fetching the script attachment, the client isn't honoring ssl_public_key

The client has this:

[client]
script_users = ALL
log_level = debug
url = https://ec2-184-73-147-11.compute-1.amazonaws.com/message-system
computer_title = ec2-174-129-92-156.compute-1.amazonaws.com
data_path = /var/lib/landscape/client
registration_password = foo
ping_url = http://ec2-184-73-147-11.compute-1.amazonaws.com/ping
include_manager_plugins = ScriptExecution
ssl_public_key = /etc/ssl/certs/landscape_server_ca.crt
account_name = standalone

exchange_interval = 30
ping_interval = 10
urgent_exchange_interval = 10

But when sending a script with an attachment to it, it failed:
[Failure instance: Traceback: <class 'landscape.lib.fetch.PyCurlError'>: Error 60: server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
/usr/lib/python2.6/dist-packages/twisted/internet/defer.py:307:errback
/usr/lib/python2.6/dist-packages/twisted/internet/defer.py:354:_startRunCallbacks
/usr/lib/python2.6/dist-packages/twisted/internet/defer.py:371:_runCallbacks
/usr/lib/python2.6/dist-packages/twisted/internet/defer.py:879:gotResult
--- <exception caught here> ---
/usr/lib/python2.6/dist-packages/twisted/internet/defer.py:821:_inlineCallbacks
/usr/lib/python2.6/dist-packages/twisted/python/failure.py:338:throwExceptionIntoGenerator
/usr/lib/python2.6/dist-packages/landscape/manager/scriptexecution.py:221:_save_attachments
/usr/lib/python2.6/dist-packages/twisted/python/threadpool.py:210:_worker
/usr/lib/python2.6/dist-packages/twisted/python/context.py:59:callWithContext
/usr/lib/python2.6/dist-packages/twisted/python/context.py:37:callWithContext
/usr/lib/python2.6/dist-packages/landscape/lib/fetch.py:98:fetch
]

The script was the sample data "print 'OK!'" one, in python (script id 2).