Incorporate the external log files in debug ball

- don't put bash command errors in log files
- add exit on fail option to repeat script
- add ability of repeat script to include external logs
diff --git a/voltha b/voltha
index c647dc1..68fdab8 100755
--- a/voltha
+++ b/voltha
@@ -576,6 +576,9 @@
 if [ "$1" == "dump" ]; then
     LOG="dump-$NAME.log"
     TS=$(date -u +"%Y%m%dT%H%M%SZ")
+    if [ ! -z "$DUMP_FROM" ]; then
+        TS=$(echo $DUMP_FROM | sed -e 's/[:-]//g')
+    fi
     WORK=$(mktemp -u -d)
     DATA=$WORK/voltha-debug-dump-$NAME-$TS
     mkdir -p $DATA