HAL rejects mount/unmount/eject on anything declared in the fstab...
So add some fstab handling facilities in the HAL backend (that duplicates internally a very tiny bit of KMountPoint features, but I can't depend on this class).

Now for mount/unmount/eject we first check if the device is in the fstab, if it's in we call the system tools using QProcess, otherwise we use HAL methods as usual.