This patch fixes the output of v2 Tacker so that vnfPkgId of
VnfInstance that are only used in v1 Tacker are not displayed
as CLI output.
This is because it is confusing for v2 users that unused vnfPkgId
(VNF Package ID) is always displayed as empty.
The vnfPkgId (VNF Package ID) remain displayed in the v1 Tacker
CLI output.
Change-Id: I4adea34e9c2c7fc51e087d2a00f47db77d67fe4a