log-dump: fix usage printout if no args are specified
log-dump: fix usage printout if no args are specified

Change-Id: I515f11e8ae4b520382ada912f5d83bd139fe2305
Reviewed-on: http://gerrit.ent.cloudera.com:8080/893
Reviewed-by: David Alves <33ea948168c114d220e0372a903be6ee60f6396e@cloudera.com>
Tested-by: jenkins

InspurUSA/kudu,EvilMcJerkface/kudu,cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,andrwng/kudu,InspurUSA/kudu,cloudera/kudu,cloudera/kudu,cloudera/kudu,EvilMcJerkface/kudu,andrwng/kudu,andrwng/kudu,EvilMcJerkface/kudu,EvilMcJerkface/kudu,cloudera/kudu,EvilMcJerkface/kudu,cloudera/kudu,cloudera/kudu,InspurUSA/kudu,EvilMcJerkface/kudu,andrwng/kudu,andrwng/kudu,helifu/kudu,EvilMcJerkface/kudu,InspurUSA/kudu,helifu/kudu,helifu/kudu,helifu/kudu,helifu/kudu,andrwng/kudu,helifu/kudu,InspurUSA/kudu,cloudera/kudu,helifu/kudu,InspurUSA/kudu,andrwng/kudu,andrwng/kudu,EvilMcJerkface/kudu,helifu/kudu,helifu/kudu,InspurUSA/kudu,InspurUSA/kudu,andrwng/kudu,InspurUSA/kudu