use correct exitcode upon ctrl-c

Co-authored-by: Kurt Garloff <[email protected]>
Signed-off-by: Matthias Büchse <[email protected]>

Author: mbuechse

Tests/add_subject.py

@@ -11,6 +11,7 @@
 import os.path
 import re
 import shutil
+import signal
 import subprocess
 import sys
 
@@ -86,3 +87,4 @@ def main(argv, cwd):
         sys.exit(1)
     except KeyboardInterrupt:
         print("Interrupted", file=sys.stderr)
+        sys.exit(128 + signal.SIGINT)