mwan3: treat SIGHUP as non-error

A return code of 129 means that the script has been killed by SIGHUP,
expected to abort an alert in case of mwan3 restart
Every other code is treated as error and the error message is logged.

packages/ns-plug/files/mwan-hooks

@@ -7,15 +7,16 @@
 
 failed_count=0
 
-# Execute all mwan scrips
+# Execute all mwan scripts
 for f in $(find /usr/libexec/mwan-hooks/ -type f -executable)
 do
-    # Execute the script
-    $f
+    # Execute the script and capture the output:
+    # avoid unwanted output if the script is terminated with a SIGHUP
+    output=$($f 2>&1)
     exit_code=$?
-    if [ $exit_code -gt 0 ]; then
+    if [[ $exit_code -gt 0 && $exit_code != 129 ]]; then
         ((failed_count++))
-        logger -t mwan3-hook "Script $f failed with exit code $exit_code"
+	logger -t mwan3-hook "Script $f returned $exit_code: $output"
     fi
 done