Address review comments 2.49, 2.51, 2.52, 2.55-57, 2.59-60, 2.62, 4.12, 4.14, 4.20-26, 4.28, 4.31, 4.33, 4.37, 4.40, 4.43-49
Merge branch 'n1k-plugin' of https://github.com/CiscoSystems/quantum into n1k-plugin