Description of problem:
Installing Fedora 22 Cloud Beta to KVM guest with a custom partition.

Version-Release number of selected component:
anaconda-22.20.11-1

The following was filed automatically by anaconda:
anaconda 22.20.11-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/blivet/formats/fs.py", line 687, in unmount
    raise FSError("umount failed")
  File "/usr/lib/python2.7/site-packages/blivet/formats/fs.py", line 896, in teardown
    return self.unmount()
  File "/usr/lib/python2.7/site-packages/blivet/osinstall.py", line 615, in umountFilesystems
    device.format.teardown()
  File "/usr/lib/python2.7/site-packages/blivet/blivet.py", line 1410, in umountFilesystems
    self.fsset.umountFilesystems(swapoff=swapoff)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/install.py", line 247, in doInstall
    storage.umountFilesystems()
  File "/usr/lib64/python2.7/threading.py", line 766, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/threads.py", line 244, in run
    threading.Thread.run(self, *args, **kwargs)
FSError: umount failed

Additional info:
addons:         com_redhat_kdump
cmdline:        /usr/bin/python2  /sbin/anaconda
cmdline_file:   BOOT_IMAGE=vmlinuz initrd=initrd.img inst.stage2=hd:LABEL=Fedora-22-x86_64 quiet
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         4.0.0-1.fc22.x86_64
product:        Fedora
release:        Cannot get release name.
type:           anaconda
version:        22