do not set $cluster on install2001

since we want it to be an aggregator
and use ganglia_new and we are getting a duplicate
definition when using old ganglia module and new
ganglia module on one host

at least this was the only difference to hooft,
where this is not causing a puppet problem

Duplicate declaration: File[/usr/lib/ganglia/python_modules]
is already declared in file /etc/puppet/manifests/ganglia.pp:224;
cannot redeclare at /etc/puppet/modules/ganglia_new/manifests/monitor/packages.pp:12

Change-Id: I4dc6ef44cbffceb34cbf3dbbfcfc918fe8236e16
RT: 8188
Merge "do not set $cluster on install2001" into production