base: Only install haveged on physical machines

Doing otherwise would conflict with vm/guest.

Installing it only in vm/host is insufficient: we have physical machines that
aren't used as hypervisors, such as wuerfel.

ansible/roles/base/tasks/02debian.yml

@@ -16,7 +16,6 @@
       - tcpdump
       - debian-goodies
       - lsof
-      - haveged
       - net-tools
       - screen
       - aptitude
@@ -30,6 +29,12 @@
       - lshw
     state: present
 
+- name: Install haveged on physical machines
+  when: 'virtualservers' not in group_names
+  apt:
+    name: haveged
+    state: present
+
 - name: make sure grml-(etc|scripts)-core is not installed
   apt:
     name: