Fix sense of NULL test in android_media_MediaScanner_extractAlbumArt.

Change-Id: I1acb4d5df71daa47ea87813db3941fd3c676cfb5
diff --git a/media/jni/android_media_MediaScanner.cpp b/media/jni/android_media_MediaScanner.cpp
index 6730e0a..b520440 100644
--- a/media/jni/android_media_MediaScanner.cpp
+++ b/media/jni/android_media_MediaScanner.cpp
@@ -350,7 +350,7 @@
     int fd = jniGetFDFromFileDescriptor(env, fileDescriptor);
     MediaAlbumArt* mediaAlbumArt =
             reinterpret_cast<MediaAlbumArt*>(mp->extractAlbumArt(fd));
-    if (mediaAlbumArt != NULL) {
+    if (mediaAlbumArt == NULL) {
         return NULL;
     }