Open JPEG file with embedded exif data.  Use exif browswer plugin and note lack
of data.  Save file and notice new jpeg has no exif data.
The problem is that the save and load parasite names are different, and since
the exif browser agrees with the save, i changed the load to jpeg-exif-data.

Patch JPEG plugin:
--- jpeg.c.~1~  2004-07-17 09:07:23.000000000 -0400
+++ jpeg.c      2004-08-05 10:57:02.000000000 -0400
@@ -1165,7 +1165,7 @@
 
              if (exif_buf_len > EXIF_HEADER_SIZE)
                {
-                 exif_parasite = gimp_parasite_new ("exif-data",
+                 exif_parasite = gimp_parasite_new ("jpeg-exif-data",
                                                     GIMP_PARASITE_PERSISTENT,
                                                     exif_buf_len, exif_buf);
                  gimp_image_parasite_attach (image_ID, exif_parasite);