tcp: fix rxt send of new data assert

We might have less than 1 mss when attempting write but more after
write, as application could be actively enqueuing more data. Relax
assert.

Type: fix

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I54a83c4460f8e022a88758f0ebd7828df711dbb9
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 069c349..e6c87b6 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1117,8 +1117,7 @@
       data = tcp_init_buffer (vm, *b);
       n_bytes = session_tx_fifo_peek_bytes (&tc->connection, data, offset,
 					    max_deq_bytes);
-      ASSERT (n_bytes == clib_min (max_deq_bytes, transport_max_tx_dequeue (
-						    &tc->connection)));
+      ASSERT (n_bytes > 0);
       b[0]->current_length = n_bytes;
       tcp_push_hdr_i (tc, *b, tc->snd_una + offset, /* compute opts */ 0,
 		      /* burst */ 0, /* update_snd_nxt */ 0);