tests: Add tests for IPSec async mode using the crypto SW scheduler

Type: test

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Iabc8f2b09ee10a82aacebd36acfe8648cf69b7d7
diff --git a/src/vnet/ipsec/esp_decrypt.c b/src/vnet/ipsec/esp_decrypt.c
index 0924351..274fbf8 100644
--- a/src/vnet/ipsec/esp_decrypt.c
+++ b/src/vnet/ipsec/esp_decrypt.c
@@ -1234,7 +1234,8 @@
 
       /* no post process in async */
       vlib_node_increment_counter (vm, node->node_index,
-				   ESP_DECRYPT_ERROR_RX_PKTS, n_left);
+				   ESP_DECRYPT_ERROR_RX_PKTS,
+				   from_frame->n_vectors);
       if (n_async_drop)
 	vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_async_drop);