Avoid deleting log file after server start.

start-jupyter

@@ -360,7 +360,6 @@ function main () {
     printf "Starting jupyter server" >&2
     local url
     url="$(extract_from_logs "^.*\Khttp://localhost:.+" "${jupyter_log}")"
-    ssh_frontend "rm -f ${jupyter_log}"
 
     local port
     port=${url#*t:}