Description of problem:
Installation hangs at "preparing to install" stage (that is the first text displayed when starting the real installation). If I look into logs, I see:

09:29:26,005 INFO program: Running... lvm pvremove --force --force --config  devices { filter=["r|/loop3$|","r|/loop4$|","r|/loop5$|","r|/loop6$|","r|/loop7$|","r|/vg_foobar-lv_swap$|","r|/vg_foobar-lv_root$|","r|/vg_foobar$|","r|/sdb1$|","r|/sdb$|"] }  /dev/sda2
09:29:26,771 ERR program:   Couldn't find device with uuid 08KHPS-Fvrh-J3VE-ZFi9-BQdj-vfJn-fVnGt9.

I saw this problem for the third time, on two different machines. It probably happens if there are some existing LVM partition on the target disk (that you selected for automatic partitioning). But it is hard to reproduce, the same installation went fine on a second attempt on one machine, but also failed on a second attempt on a different machine. So it's not really deterministic.

I'm not sure why anaconda tries to remove the LVs in the first place, when it can just wipe the disk clean.

Version-Release number of selected component (if applicable):
anaconda 18.6.8
F18 Alpha

How reproducible:
sometimes

Steps to Reproduce:
1. have existing LVM partitions on a disk
2. boot anaconda
3. select the disk for automatic partitioning
4. start the installation