Hybrid persitent fixed (openSuSE 12.3)

Hybrid persistent does not work any more. 

First, the whole device is mounted as iso and the loop-back trick for the RW partion does not work any more. This can be fixed by using offset 0 in isohybrid.

Using the partion as iso location allows to create/use a RW partion. The code has one bug for this case: It tries to create the partion as part of the ISO partion (eg. /dev/sda1p4).
This is fixed by the second commit.

At shutdown, an issue is remaining: The overlayed file systems (clic) are not properly stopped, so that ext4 error and/or a corrupted COW file is reported.

Related to https://bugzilla.novell.com/show_bug.cgi?id=814172