Description of problem:
Exception raised when I clicked on my BTRFS loop device.

Version-Release number of selected component:
blivet-gui-2.0.2-3.fc25

Additional info:
reporter:       libreport-2.8.0
cmdline:        /usr/bin/python3 /usr/bin/blivet-gui
executable:     /usr/bin/blivet-gui
kernel:         4.11.11-200.fc25.x86_64
pkg_fingerprint: 4089 D8F2 FDB1 9C98
pkg_vendor:     Fedora Project
runlevel:       N 5
type:           Python3
uid:            1000

Truncated backtrace:
client.py:163:remote_call:AttributeError: 'LoopDevice' object has no attribute 'disk'
Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/blivetgui/communication/server.py", line 307, in _call_utils_method
    ret = utils_method(*args)
  File "/usr/lib/python3.5/site-packages/blivetgui/blivet_utils.py", line 435, in get_roots
    roots.add(self._get_root_device(member))
  File "/usr/lib/python3.5/site-packages/blivetgui/blivet_utils.py", line 458, in _get_root_device
    return blivet_device.disk
AttributeError: 'LoopDevice' object has no attribute 'disk'


Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/blivetgui/list_devices.py", line 193, in on_disk_selection_changed
    self.blivet_gui.update_physical_view()
  File "/usr/lib/python3.5/site-packages/blivetgui/blivetgui.py", line 150, in update_physical_view
    self.list_parents.update_parents_list(self.list_devices.selected_device)
  File "/usr/lib/python3.5/site-packages/blivetgui/list_parents.py", line 42, in update_parents_list
    root_devices = self.blivet_gui.client.remote_call("get_roots", selected_device)
  File "/usr/lib/python3.5/site-packages/blivetgui/communication/client.py", line 163, in remote_call
    raise type(ret.exception)(str(ret.exception) + "\n" + ret.traceback)  # pylint: disable=maybe-no-member
AttributeError: 'LoopDevice' object has no attribute 'disk'
Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/blivetgui/communication/server.py", line 307, in _call_utils_method
    ret = utils_method(*args)
  File "/usr/lib/python3.5/site-packages/blivetgui/blivet_utils.py", line 435, in get_roots
    roots.add(self._get_root_device(member))
  File "/usr/lib/python3.5/site-packages/blivetgui/blivet_utils.py", line 458, in _get_root_device
    return blivet_device.disk
AttributeError: 'LoopDevice' object has no attribute 'disk'


Local variables in innermost frame:
self: <blivetgui.communication.client.BlivetGUIClient object at 0x7f2da4ed55f8>
answer: 'Proxy ID, 750'
pickled_data: b'\x80\x03(C\t403240710q\x00X\x04\x00\x00\x00callq\x01X\t\x00\x00\x00get_rootsq\x02]q\x03cblivetgui.communication.proxy_utils\nProxyID\nq\x04)\x81q\x05}q\x06X\x02\x00\x00\x00idq\x07K\nsbatq\x08.'
ret: <blivetgui.communication.client.ClientProxyObject object at 0x7f2da3e96160>
method: 'get_roots'
args: (<blivetgui.communication.client.ClientProxyObject object at 0x7f2da479d128>,)