Upgrade to libpcap 1.7.4.

Bug: http://b/24902618
Change-Id: I1bb6c1163b573eb01b4bed7c494a6d447e8d45cf
diff --git a/pcap-pf.c b/pcap-pf.c
index 8de6e58..e03b2ed 100644
--- a/pcap-pf.c
+++ b/pcap-pf.c
@@ -22,11 +22,6 @@
  *	Extraction/creation by Jeffrey Mogul, DECWRL
  */
 
-#ifndef lint
-static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.97 2008-04-14 20:40:58 guy Exp $ (LBL)";
-#endif
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -242,7 +237,7 @@
 		return (-1);
 	}
 	return (ret);
-}                           
+}
 
 static int
 pcap_stats_pf(pcap_t *p, struct pcap_stat *ps)