Add ('--') separator for /bin/nsenter example.
Add ('--') separator for /bin/nsenter example.

Resolves https://github.com/cisco/cisco-network-puppet-module/issues/413
mikewiebe/cisco-network-puppet-module,cisco/cisco-network-puppet-module,mikewiebe/cisco-network-puppet-module,cisco/cisco-network-puppet-module,cisco/cisco-network-puppet-module,cisco/cisco-network-puppet-module,mikewiebe/cisco-network-puppet-module,mikewiebe/cisco-network-puppet-module