Actually apply version script to libnativebridge

This way the list of exported symbols will be limited by symbols
that need to be exported.

Test: make
Change-Id: Iffc8e0b3b589e78f5d213f75971a54b473760c94
diff --git a/libnativebridge/Android.bp b/libnativebridge/Android.bp
index 59cd033..a5f0142 100644
--- a/libnativebridge/Android.bp
+++ b/libnativebridge/Android.bp
@@ -17,6 +17,7 @@
         "liblog",
     ],
 
+    version_script: "libnativebridge.map.txt",
     stubs: {
         symbol_file: "libnativebridge.map.txt",
         versions: ["1"],