i3bar: draw workspace buttons at x=0 instead of x=1

This makes the workspace buttons align with the window borders, which is
particularly visible with color configurations like the one in this
screenshot: http://i.imgur.com/CH8srF5.png

fixes #687

i3bar/src/xcb.c

@@ -1608,7 +1608,7 @@ void reconfig_windows(bool redraw_bars) {
  */
 void draw_bars(bool unhide) {
     DLOG("Drawing Bars...\n");
-    int i = 1;
+    int i = 0;
 
     refresh_statusline();
 
@@ -1766,7 +1766,7 @@ void draw_bars(bool unhide) {
             unhide = true;
         }
 
-        i = 1;
+        i = 0;
     }
 
     /* Assure the bar is hidden/unhidden according to the specified hidden_state and mode */