eve-tool: only pkill oldest zedbox

we saw that a child process of zedbox got killed with USR2
(no signal handler defaults to SIGTERM).

My theory is that the following happened:
1. zedbox called fork()
2. now there are two zedbox processes
3. pkill finds two zedbox processes
4. child process of zedbox calls exec and remove USR2 handler
5. pkill sends USR2 to both PIDs
6. zedbox starts http debug as usual
7. child process (now supposed to do something different) gets killed

perhaps fixes #4002

Signed-off-by: Christoph Ostarek <christoph@zededa.com>

pkg/dom0-ztools/rootfs/bin/eve

@@ -100,7 +100,7 @@ http_debug_request() {
     fi
 
     if [ "$running" = "0" ]; then
-        pkill -USR2 zedbox
+        pkill -o -USR2 zedbox
     fi
 
     printf "POST %s HTTP/1.0\r\n\r\n" "$URL" | nc 127.1 6543
@@ -230,7 +230,7 @@ __EOT__
           fi
           ;;
  http-debug) if [ -z "$2" ] || [ "$2" = "start" ]; then
-              pkill -USR2 zedbox
+              pkill -o -USR2 zedbox
               echo "Listening on :6543 -- use 'eve http-debug stop' to stop"
           elif [ "$2" = "stop" ]; then
               printf "POST /stop HTTP/1.0\r\n\r\n" | nc 127.1 6543
@@ -247,7 +247,7 @@ __EOT__
           echo "Your information can be found in logread"
           ;;
  memory-monitor-update-config)
-          pkill -SIGHUP /sbin/memory-monitor
+          pkill -o -SIGHUP /sbin/memory-monitor
           echo "Updated memory-monitor configuration"
           ;;
  verbose) # first lets find our piping process