Don't set governor on VMs

Change-Id: Ifa26361845a6841eff1ab49e6d6542946898c426

linux/system/cpu.sls

     - name: ondemand
     - enable: false
 
+{%- if grains.get('virtual', None) in ['physical', None] %}
+{#- Governor cannot be set in VMs, etc. #}
+
 /etc/sysfs.d/governor.conf:
   file.managed:
     - source: salt://linux/files/governor.conf.jinja
 {%- endfor %}
 
 {%- endif %}
+
+{%- endif %}