[spp] [PATCH] docs: fix warning in compilation

[ogawa.yasufumi@lab.ntt.co.jp]

From: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>

Design section of spp_vf includes malformed code block as described
bellow.

    .. code-block:: none

        /tmp/spp_pcap.20181108110600.ring0.1.2.pcap.lz4.tmp
    This example shows that ``receiver`` thread receives ``start`` ...

There is no blank line the end of the code block. It is warned while
compilation.

This update is to fix it by inserting blank line.

Signed-off-by: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
---
 docs/guides/spp_vf/design.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/docs/guides/spp_vf/design.rst b/docs/guides/spp_vf/design.rst
index 0f3e5c8..23246ba 100644
--- a/docs/guides/spp_vf/design.rst
+++ b/docs/guides/spp_vf/design.rst
@@ -184,6 +184,7 @@ YYYYMMDDhhmmss is the time when ``spp_pcap`` receives ``start`` command.
 .. code-block:: none
 
     /tmp/spp_pcap.20181108110600.ring0.1.2.pcap.lz4.tmp
+
 This example shows that ``receiver`` thread receives ``start`` command at
 20181108110600.  Port is ring:0, wcore_num is 1 and sequential number is 2.
 
-- 
2.7.4