FTP Client: Pressing up in deeper level doesn't load root folder content

When navigating to a folder, that is deeper than 1 level, pressing up many times doesn't produce expected result. Root folder content is not loaded.

To reproduce:
1. Start fluidlauncher
2. Start FTP Client in fluidlauncher
3. Press Connect button (to ftp.qt.nokia.com) and wait untill root folder content is shown in the list below.
4. Navigate to demos -> mac
5. Press up folder icon two times

Expected: Root folder content is loaded. Up button is disabled.
Actual: Demos folder content is loaded. Up button is disabled.

If coninuing from here, navigating from demos inside mac folder and pressing up again the root folder content is loaded.

More details in privat JIRA: https://qtrequirements.troll.no/browse/QT-4745