Rsync: support for backupninja's test option (#8196)

handlers/rsync.in

@@ -920,6 +920,10 @@ function set_filelist {
 
 function set_rsync_options {
 
+  if [ "$test" ]; then
+    rsync_options="$rsync_options --dry-run"
+  fi
+
   if [ "$numericids" != "0" ]; then
     rsync_options="$rsync_options --numeric-ids"
   fi