Feature: pengine: Support id-ref in nvpair with optional "name"

If "name" isn't specified, it inherits the name from the referenced
nvpair.
Test: pengine: Support id-ref in nvpair with optional "name"
Merge pull request #425 from gao-yan/nvpair-id-ref

Feature: pengine: Support id-ref in nvpair with optional "name"