Description of problem:
Beaker system with DELL PERC 5/i (a PCI Express based SAS RAID controller) is failing installation of RHEL7.2 GA with following call trace:

anaconda 21.48.22.56-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/blivet/devicetree.py", line 384, in processActions
    if dep.exists and dep.dependsOn(action.device.disk):
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 374, in doIt
    self.devicetree.processActions(callbacks)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 224, in turnOnFilesystems
    storage.doIt(callbacks)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/install.py", line 186, in doInstall
    turnOnFilesystems(storage, mountOnly=flags.flags.dirInstall, callbacks=callbacks_reg)
  File "/usr/lib64/python2.7/threading.py", line 764, 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: 'DiskDevice' object has no attribute 'disk'


Version-Release number of selected component (if applicable):
RHEL7.2GA

How reproducible:
high

Steps to Reproduce:
1. install RHEL7.2GA on dell-pe2950-02

Actual results:
installation fails

Expected results:
system can be installed

Additional info: