Fix text stroke color reference in the concat command.

dcc/concat.py

@@ -92,7 +92,7 @@ class Concat(dcc.doom_base.Wad):
             )
             img.trim(reset_coords=True)
             img.border("graya(25%, 25%)", 10, 10)
-            img.border(dcc.config.TEXT_STROKE_COLOR, 16, 16)
+            img.border(self.thumbnail_text_stroke, 16, 16)
             # for this to work... the image needs to have a width that's a
             # multiple of 8.  dude whyyyyyyy
             padfactor = 8