improve promote script to use rsync instead of cp

releng.control/promote.sh

@@ -165,7 +165,7 @@ then
      exitCode=$?
      if [ $exitCode != 0 ]
      then
-	     nTrys=$(( nTrys + 1 ))
+	     nTrys=$(( $nTrys + 1 ))
 	     if [ $verboseFlag ] ; then
              echo "rsync failed with $exitCode. Retrying $nTrys times."
 		     if [ $nTrys > $maxTrys ] ; then