proc proccon: duplicate software trace moved to warning

We cannot assure that software imported into skydive from outside
doesn't have the cmdline duplicated (same server, two softwares, same
cmdline).
To avoid hidding more important problems, we are moving this "error" as
warning.

Author: adrianlzt

topology/probes/proccon/proccon.go

@@ -209,7 +209,7 @@ func (p *Probe) processHostMetrics(serverNode *graph.Node, metrics []Metric) int
 			continue
 		} else if len(childNodes) > 1 {
 			// This should not happen
-			logging.GetLogger().Errorf("Found more than one Software node for Server node '%v' and cmdline '%s': %+v. Ignoring", nodeName(serverNode), metric.Tags["cmdline"], childNodes)
+			logging.GetLogger().Warningf("Found more than one Software node for Server node '%v' and cmdline '%s': %+v. Ignoring", nodeName(serverNode), metric.Tags["cmdline"], childNodes)
 			numberOfErrors++
 			continue
 		}