Network routines: fix a Coverity warning

The warning was:
CID 602256 (luigirizzo#1 of 2): Buffer not null terminated (BUFFER_SIZE_WARNING)
CID 602256 (luigirizzo#2 of 2): Buffer not null terminated (BUFFER_SIZE_WARNING)
buffer_size_warning: Calling strncpy with a maximum size argument of 16 bytes
on destination array ifr.ifr_ifrn.ifrn_name of size 16 bytes might leave
the destination string unterminated.

inet.c

@@ -905,7 +905,7 @@ pcap_lookupnet(device, netp, maskp, errbuf)
 	/* XXX Work around Linux kernel bug */
 	ifr.ifr_addr.sa_family = AF_INET;
 #endif
-	(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+	(void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 	if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
 		if (errno == EADDRNOTAVAIL) {
 			(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
@@ -925,7 +925,7 @@ pcap_lookupnet(device, netp, maskp, errbuf)
 	/* XXX Work around Linux kernel bug */
 	ifr.ifr_addr.sa_family = AF_INET;
 #endif
-	(void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+	(void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 	if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
 		(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 		    "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));