Description of problem:
I was trying to install Fedora 21 over my Fedora 20 install. My Fedora 20 installation has a btrfs volume with subvolumes for / and /home, as well as a separate ext3 /boot partition and a swap partition. I selected the /home btrfs subvolume and clicked the button to remove it. I selected the option to remove other volumes on this partition. There was a message asking if I was sure I wanted to do this. After I agreed to that, Anaconda crashed.

Version-Release number of selected component:
anaconda-core-21.48.6-1.fc21.x86_64

The following was filed automatically by anaconda:
anaconda 21.48.6-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/blivet/devicetree.py", line 426, in _removeDevice
    raise ValueError("Cannot remove non-leaf device '%s'" % dev.name)
  File "/usr/lib/python2.7/site-packages/blivet/devicetree.py", line 496, in registerAction
    self._removeDevice(action.device)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 1296, in destroyDevice
    self.devicetree.registerAction(action)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/custom.py", line 1703, in _destroy_device
    self._storage_playground.destroyDevice(device)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/custom.py", line 122, in decorated
    return func(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/custom.py", line 1826, in on_remove_clicked
    self._destroy_device(dev)
ValueError: Cannot remove non-leaf device 'sdc3'

Additional info:
cmdline:        /usr/bin/python  /sbin/anaconda --liveinst --method=livecd:///dev/mapper/live-base
cmdline_file:   initrd=/isolinux/initrd0.img root=live:UUID=B8F8-F63E rootfstype=auto ro rd.live.image quiet  rhgb rd.luks=0 rd.md=0 rd.dm=0 BOOT_IMAGE=/isolinux/vmlinuz0 
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.16.1-301.fc21.x86_64
other involved packages: python-blivet-0.62-1.fc21.noarch, anaconda-gui-21.48.6-1.fc21.x86_64
product:        Fedora
release:        Fedora release 21 (Twenty One)
type:           anaconda
version:        21