vlib: add format_vnet_buffer_no_chain

 - add format_vnet_buffer and format_vnet_buffer_no_chain to mirror
   format_vlib_buffer and format_vlib_buffer_no_chain
 - format_vnet_buffer used to be the "no chain" version, replace all of
   its current use with the corresponding format_vnet_buffer_no_chain
 - add a function to dump vnet buffer details from gdb

Type: improvement

Change-Id: I143ce845f80e7ef937ea33a557b6e3b5988c5b8f
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/vnet/pg/stream.c b/src/vnet/pg/stream.c
index 686627b..605567c 100644
--- a/src/vnet/pg/stream.c
+++ b/src/vnet/pg/stream.c
@@ -102,9 +102,8 @@
   pg_output_trace_t *t = va_arg (*va, pg_output_trace_t *);
   u32 indent = format_get_indent (s);
 
-  s = format (s, "%Ubuffer 0x%x: %U",
-	      format_white_space, indent,
-	      t->buffer_index, format_vnet_buffer, &t->buffer);
+  s = format (s, "%Ubuffer 0x%x: %U", format_white_space, indent,
+	      t->buffer_index, format_vnet_buffer_no_chain, &t->buffer);
 
   s = format (s, "\n%U%U", format_white_space, indent,
 	      format_ethernet_header_with_length, t->buffer.pre_data,