Pending changes can cause keyerror

[Walter Doekes]

Apparently @vilitux ran into this:

  File "/usr/local/bin/proxmove", line 464, in from_dict
    vm.get_config()  # get config and check for pending changes at once
  File "/usr/local/bin/proxmove", line 495, in get_config
    dict_['key'], dict_['value'], dict_['pending']))
KeyError: 'value'

We expect both value and pending to be set, but apparently that's not always the case (updates in smbios?):

            pending = []
            for dict_ in pending_config:
                keys = dict_.keys()
                if keys == set(['key', 'value']):
                    assert next_config.get(dict_['key']) == dict_['value']
                else:
                    pending.append('{!r}({!r}=>{!r})'.format(
                        dict_['key'], dict_['value'], dict_['pending']))
            if pending:
                # Contains 'pending' changes. Refuse to continue.
                raise ProxmoxVm.Error(
                    'VM {!r} contains pending changes: {}'.format(
                        self.name, ', '.join(pending)))