CLOUDSTACK-3383: Fetch CPU utilization more reliable.

This should fix that we can't gather CPU statistics on hypervisors
> Ubuntu 12.04

Author: wido

plugins/hypervisors/kvm/src/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java

@@ -3253,7 +3253,7 @@ private Answer execute(CheckHealthCommand cmd) {
     private Answer execute(GetHostStatsCommand cmd) {
         final Script cpuScript = new Script("/bin/bash", s_logger);
         cpuScript.add("-c");
-        cpuScript.add("idle=$(top -b -n 1|grep Cpu\\(s\\):|cut -d% -f4|cut -d, -f2);echo $idle");
+        cpuScript.add("idle=$(top -b -n 1| awk -F, '/^[%]*[Cc]pu/{$0=$4; gsub(/[^0-9.,]+/,\"\"); print }'); echo $idle");
 
         final OutputInterpreter.OneLineParser parser = new OutputInterpreter.OneLineParser();
         String result = cpuScript.execute(parser);