In the meantime, add some static methods in FakeVolume for ease of use
and add info() method with "property" decorator in FakeResource to allow
those static methods to get fake information.
Change-Id: I98ad520f32afd529fda77a4592f645130282537f
Co-Authored-By: xiexs <xiexs@cn.fujitsu.com>
Implements: blueprint improve-volume-unittest-framework