android: ensure the asset manager is initialised (hint: it's not).

src/platform/android/androidapp.cpp

@@ -276,6 +276,8 @@ AndroidAppData *g_data;
 
 void android_main(android_app* native_app)
 {
+    Log::Info("Java layer calling main() for app 0x%08lx", (long)native_app);
+
     g_data = new AndroidAppData();
     g_data->m_native_app = native_app;
 

src/sys/file.cpp

@@ -63,6 +63,7 @@ class FileData
         if (err != CELL_FS_SUCCEEDED)
             m_fd = -1;
 #elif __ANDROID__
+        ASSERT(g_assets);
         m_asset = AAssetManager_open(g_assets, file.C(), AASSET_MODE_UNKNOWN);
 #elif HAVE_STDIO_H
         /* FIXME: no modes, no error checking, no nothing */