patch for Atlanta

[Bill Haneman <bill haneman sun com>]

The Atlanta Metacity theme, which is otherwise very good for
accessibility, draws window borders that are very hard to see for
"inverse" gtk+ themes like HighContrastInverse.

Filed a bug on this
http://bugzilla.gnome.org/show_bug.cgi?id=98745

tiny patch is attached which solves this problem without affecting the
appearance when using Default or other gtk+ themes.  What do you think
Havoc, OK to commit?

-Bill