ui-log: make some variables 'static'

These are not used outside this file and are not declared.

Signed-off-by: John Keeping <john@keeping.me.uk>

ui-log.c

@@ -12,7 +12,7 @@
 #include "ui-shared.h"
 #include "argv-array.h"
 
-int files, add_lines, rem_lines;
+static int files, add_lines, rem_lines;
 
 /*
  * The list of available column colors in the commit graph.