Added option to sync vm config via csync2

When save_config_on_stop AND sync_config_on_save is enabled the config gets synced with csync2 -x vm.conf to all nodes configured in csync2. This will make sure that wherever the VM starts it will inherit the config changes.

I'd be in favor of renaming 'sync_config_on_save'  to 'sync_config_on_stop'. Then have save_config_on_stop be implied when sync_config_on_stop is enabled.

You'd never use the 'sync_config_on_save' option without setting save_config_on_stop, so why not make it a single option they have to set for the sync?