Fix issues with running test in open source

Summary: Travis builds have been broken for a while. This diff fixes some of the issues surrounding bad buck file configuration as well as missing jni.h file.

Reviewed By: astreet

Differential Revision: D4148724

fbshipit-source-id: 1e284db61280326a4bcbb9337e804a4804348aa6

lib/jni/BUCK

@@ -0,0 +1,17 @@
+# Copyright (c) 2014-present, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+cxx_library(
+  name = 'jni',
+  force_static = True,
+  header_namespace = '',
+  exported_headers = [
+    'jni.h',
+    'real/jni.h',
+  ],
+  visibility = ['PUBLIC'],
+)