GRE tests and fixes

Change-Id: I234240e9bdd4b69ad64a17b1449ae1e81c0edaca
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/.gitignore b/.gitignore
index 5a8384a..cec432c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -84,3 +84,6 @@
 /vpp-api/python/vpp_papi.egg-info
 /vpp-api/python/vpp_papi/memclnt.py
 /vpp-api/python/vpp_papi/vpe.py
+
+# Build files in the test directory
+/test/*.ok