refactor: bubble up error handling so that standard exit codes can be set at the top-level

LogFail shouldn't be called internally if at all possible.

plugins/cron/src/subcommands/subcommands.go

@@ -33,7 +33,7 @@ func main() {
 			err = cron.CommandReport(appName, *format, infoFlag)
 		}
 	default:
-		common.LogFail(fmt.Sprintf("Invalid plugin subcommand call: %s", subcommand))
+		err = fmt.Errorf("Invalid plugin subcommand call: %s", subcommand)
 	}
 
 	if err != nil {

plugins/cron/src/triggers/triggers.go

@@ -28,7 +28,7 @@ func main() {
 		appName := flag.Arg(0)
 		err = cron.ReportSingleApp(appName, "", "")
 	default:
-		common.LogFail(fmt.Sprintf("Invalid plugin trigger call: %s", trigger))
+		err = fmt.Errorf("Invalid plugin trigger call: %s", trigger)
 	}
 
 	if err != nil {