Description of problem:
just after selecting disk to install on and clicking on done

Version-Release number of selected component:
anaconda-21.37-1

The following was filed automatically by anaconda:
anaconda 21.37-1 exception report
Traceback (most recent call first):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/bootloader.py", line 1356, in is_valid_stage2_device
    if self.stage2_device.type == "mdarray" and \
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 1661, in sanityCheck
    self.bootloader.is_valid_stage2_device(stage2)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/helpers.py", line 94, in checkStorage
    exns = self.storage.sanityCheck()
  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 227, in run
    threading.Thread.run(self, *args, **kwargs)
AttributeError: 'NoneType' object has no attribute 'type'

Additional info:
cmdline:        /usr/bin/python  /sbin/anaconda
cmdline_file:   BOOT_IMAGE=/images/pxeboot/vmlinuz inst.stage2=hd:LABEL=Fedora\x20rawhide\x20x86_64 quiet
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.15.0-0.rc7.git0.1.fc21.x86_64
product:        Fedora
release:        Cannot get release name.
type:           anaconda
version:        rawhide