system-config-samba behaves badly if it can't acquire PolicyKit authentications. It should e.g. rather show an error dialog and let the user try again. For this, python-slip should probably be enhanced so others can profit as well.

+++ This bug was initially created as a clone of Bug #494896 +++

Description of problem:
Currently when system-config-samba is launched through an remote SSH session with X11 forwarding, we get a backtrace: 
https://bugzilla.redhat.com/show_bug.cgi?id=490050#c6

"When logged in through SSH, you don't have a ConsoleKit session and therefore
aren't allowed to even acquire the authorization needed for configuring Samba.
I'm not sure if/how you can tweak the PolicyKit policy to be able to do that
over SSH. I agree that the tool should display a dialog indicating the problem,
though -- I've put a hold on about anything PolicyKit related because upstream
is revamping the whole thing and I don't want to make efforts now and have to
do them again later." See https://bugzilla.redhat.com/show_bug.cgi?id=490050#c8

As a user, I'd like system-config-samba to prompt me to ask for elevated privileges instead of display an error message.

Version-Release number of selected component (if applicable):
system-config-samba-1.2.72-1.fc11.noarch

How reproducible:
Always

Steps to Reproduce:
1. ssh REMOTE-HOST system-config-samba
  
Actual results:
Traceback (most recent call last):
  File "/usr/bin/system-config-samba", line 49, in <module>
    mainWindow.MainWindow (debug_flag = debug_flag, use_dbus = use_dbus)
  File "/usr/share/system-config-samba/mainWindow.py", line 104, in __init__
    self.samba_data = sambaConfig.SambaConfig (self.samba_backend)
  File "/usr/lib/python2.6/site-packages/scsamba/core/sambaConfig.py", line 29,
in __init__
    self.parseFile ()
  File "/usr/lib/python2.6/site-packages/scsamba/core/sambaConfig.py", line 32,
in parseFile
    return self.parse (self.backend.readSmbConf ())
  File "/usr/lib/python2.6/site-packages/slip/dbus/polkit.py", line 48, in
enable_proxy_wrapper
    return func (*p, **k)
  File "/usr/lib/python2.6/site-packages/scsamba/dbus/proxy/sambaBackend.py",
line 48, in readSmbConf
    return self.dbus_interface.readSmbConf ()
  File "/usr/lib/python2.6/site-packages/dbus/proxies.py", line 68, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/python2.6/site-packages/dbus/proxies.py", line 140, in
__call__
    **keywords)
  File "/usr/lib/python2.6/site-packages/dbus/connection.py", line 630, in
call_blocking
    message, timeout)
dbus.exceptions.DBusException:
org.fedoraproject.slip.dbus.service.PolKit.NotAuthorizedException.org.fedoraproject.config.samba.configure:


Expected results:
Pretty GUI.

Additional info: