The return value of get_by_name_or_id in the volume_types module
returns a dictionary.
During the function call to _is_multiattach, the getattr() returns
{}(default value) because a dictionary is passed instead of an object.
After importing the cinder.objects.volume_type module,
the current function call to get_by_name_or_id() returns an object
hence getattr() will return the appropriate extra_specs instead of
the default value({}).
Closes-Bug: 1790840
Change-Id: I869bc0c9b18887da1ea83f855d255557f0f3cba0
(cherry picked from commit 7f85be4186)
2d8f2dc117