Revert "config.c: bump up the CONF_VER to 2 because I just added a new configuration for tab_zoom."

I will fix this in a correct way.

This reverts commit 19491ac0bb.

src/bin/config.c

@@ -5,7 +5,7 @@
 #include "config.h"
 #include "main.h"
 
-#define CONF_VER 2
+#define CONF_VER 1
 
 #define LIM(v, min, max) {if (v >= max) v = max; else if (v <= min) v = min;}