pcap recorder: include vim indenting rules as comment

Change-Id: Idbc4521053610d55c9c32eff950ed8fa68dda171
diff --git a/src/osmo_gsm_tester/pcap_recorder.py b/src/osmo_gsm_tester/pcap_recorder.py
index 8a63b30..8b1fe82 100644
--- a/src/osmo_gsm_tester/pcap_recorder.py
+++ b/src/osmo_gsm_tester/pcap_recorder.py
@@ -57,3 +57,5 @@
 
     def running(self):
         return not self.process.terminated()
+
+# vim: expandtab tabstop=4 shiftwidth=4