Handle multiple nexus switches

Puppet 2.7.11 does not handle dependencies between
custom defines that have been passed an array and
other resources when the -> syntax is used.

This patch changes it to use a require.
Merge pull request #164 from michaeltchapman/bug/1213206

Handle multiple nexus switches
Merge branch 'multi-node' of https://github.com/CiscoSystems/grizzly-manifests into bp/ha.g2

Conflicts:
	manifests/core.pp