Android: Fixed trying to read from APK expansion files without version hint set.

This also fixed overwriting the asset error message which is more useful if no
APK expansion files are available and the requested file was not found.

src/core/android/SDL_android.c

@@ -790,7 +790,10 @@ fallback:
                 "openAPKExpansionInputStream", "(Ljava/lang/String;)Ljava/io/InputStream;");
             inputStream = (*mEnv)->CallObjectMethod(mEnv, context, mid, fileNameJString);
 
-            if (Android_JNI_ExceptionOccurred(SDL_FALSE)) {
+            /* Exception is checked first because it always needs to be cleared.
+             * If no exception occurred then the last SDL error message is kept.
+             */
+            if (Android_JNI_ExceptionOccurred(SDL_FALSE) || !inputStream) {
                 goto failure;
             }
         }