Fix unittests broken by commit 2bb5c911

File "../test/ganeti.hooks_unittest.py", line 239, in setUp
  self.lu = FakeLU(FakeProc(), self.op, self.context, None)
File "…/ganeti/cmdlib.py", line 92, in __init__
  self.LogStep = processor.LogStep
AttributeError: FakeProc instance has no attribute 'LogStep'

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>