VPP-1430: remove unnecessary padding

A copy/paste mistake caused to add padding to the buffer used to send
data.

Change-Id: I04d8dfec4ae195927be1675c5ce8b30230d5b376
Signed-off-by: Marco Varlese <marco.varlese@suse.com>
diff --git a/test/test_sctp.py b/test/test_sctp.py
index f77b9dc..4d04aa0 100644
--- a/test/test_sctp.py
+++ b/test/test_sctp.py
@@ -68,7 +68,7 @@
             self.logger.critical(error)
             self.assertEqual(error.find("failed"), -1)
 
-        error = self.vapi.cli("test echo client mbytes 1" +
+        error = self.vapi.cli("test echo client mbytes 10" +
                               " appns 1" +
                               " fifo-size 4" +
                               " no-output test-bytes syn-timeout 3" +