suricatasc: exit successfully on keyboardinterrupt

(cherry picked from commit 84ffe92873)

python/suricata/sc/suricatasc.py

@@ -285,3 +285,4 @@ class SuricataSC:
                     print(json.dumps(cmdret["message"], sort_keys=True, indent=4, separators=(',', ': ')))
         except KeyboardInterrupt:
             print("[!] Interrupted")
+            sys.exit(0)