Apply version-script to libaaudio library.

In previous attempt it was mistakenly applied to cc_library_header
instead of the actual library. Do it correctly this time.
The intention of this change is to hide unintentionally
exported symbols from the library.

Bug: http://b/69603741
Test: make
Change-Id: I47967abea0b39aec05e80823c9eb3fe53f9fa591
diff --git a/media/libaaudio/src/Android.bp b/media/libaaudio/src/Android.bp
index c875436..848e42a 100644
--- a/media/libaaudio/src/Android.bp
+++ b/media/libaaudio/src/Android.bp
@@ -11,6 +11,7 @@
     ],
     header_libs: ["libaaudio_headers"],
     export_header_lib_headers: ["libaaudio_headers"],
+    version_script: "libaaudio.map.txt",
 
     srcs: [
         "core/AAudioAudio.cpp",