When get diagnostics on host only get running ones

When tried to get instance diagnostics on a particular hypervisor,
return only running instance's diagnostices.

Change-Id: I0a4269c6056248e0bdbd2a600c38b9c1ad643091
Fix vcpu quora range check

vcpu quota is -1 or [1000, 18446744073709551]

Change-Id: Ic6b12c02e92f6a54f5f86d2f7454ae6616859eba