fix dstat color

dstat_color.diff

--- dstat	2012-10-18 23:05:42.783979537 +0900
+++ /usr/bin/dstat	2012-10-18 23:02:31.767976670 +0900
@@ -1633,9 +1633,9 @@
             'debug': ansi['darkred'],
             'input': ansi['darkgray'],
             'text_lo': ansi['gray'],
-            'text_hi': ansi['darkgray'],
-            'unit_lo': ansi['darkgray'],
-            'unit_hi': ansi['darkgray'],
+            'text_hi': ansi['gray'],
+            'unit_lo': ansi['gray'],
+            'unit_hi': ansi['gray'],
             'colors_lo': (ansi['red'], ansi['yellow'], ansi['green'], ansi['blue'],
                           ansi['cyan'], ansi['white'], ansi['darkred'], ansi['darkgreen']),
             'colors_hi': (ansi['darkred'], ansi['darkyellow'], ansi['darkgreen'], ansi['darkblue'],