interface: fix pcap tx/rx trace cli handling

Provide default packet_to_capture value. Display interface name
correctly for "pcap tx/rx trace status".

Type: fix

Signed-off-by: John Lo <loj@cisco.com>
Change-Id: I7064d0dbea236a9aff68bba7fbaf2c4a73b16c6f
Signed-off-by: John Lo <loj@cisco.com>
diff --git a/src/vppinfra/pcap.h b/src/vppinfra/pcap.h
index 893c67b..c3e1fef 100644
--- a/src/vppinfra/pcap.h
+++ b/src/vppinfra/pcap.h
@@ -193,6 +193,8 @@
   u32 min_packet_bytes, max_packet_bytes;
 } pcap_main_t;
 
+#define PCAP_DEF_PKT_TO_CAPTURE (100)
+
 #endif /* included_vppinfra_pcap_h */
 
 /*