This patch updates the v2 API reference according to
the current implementation.
The main update APIs are as follows:
* Show VNF instance
* List VNF instance
* Change Current VNF Package
* Show VNF LCM operation occurrence
* List VNF LCM operation occurrence
* Fail a VNF LCM operation occurrence
* Create a new subscription
* Show subscription
* List subscription
Change-Id: Idca22a874b746c02e9d97f4ca08a1cfcee76ccc3