MTP: Fix getThumbnail

The thumbnail size was not being passed to the MTP stack so getThumbnail
was returning zero length data.

Bug: 13747419

Change-Id: I309d35b5c46ab5f631c0dcb5981f7896bb5a2ed5

media/jni/android_mtp_MtpDatabase.cpp

@@ -849,6 +849,7 @@ void* MyMtpDatabase::getThumbnail(MtpObjectHandle handle, size_t& outThumbSize)
                 result = malloc(exifdata->size);
                 if (result) {
                     memcpy(result, exifdata->data, exifdata->size);
+                    outThumbSize = exifdata->size;
                 }
             }
             exif_data_unref(exifdata);