api: implement ipfix_flush

-Migrate tests to api and cleanup:
  '# FIXME this should be an API call' in tests.

Type: feature

Change-Id: I715f9f8acc0f2af9c974ea221b2aea46692a6218
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/src/vnet/ipfix-export/ipfix_export.api b/src/vnet/ipfix-export/ipfix_export.api
index 9bd3790..8b13c3b 100644
--- a/src/vnet/ipfix-export/ipfix_export.api
+++ b/src/vnet/ipfix-export/ipfix_export.api
@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-option version = "1.0.0";
+option version = "1.0.1";
 
 /** \brief Configure IPFIX exporter process request
     @param client_index - opaque cookie to identify the sender
@@ -142,6 +142,11 @@
     u8 transport_protocol;
 };
 
+autoreply define ipfix_flush {
+    u32 client_index;
+    u32 context;
+};
+
 /*
  * Local Variables:
  * eval: (c-set-style "gnu")