init: call only once window_root_grabbuttons() on start

Signed-off-by: Julien Danjou <julien@danjou.info>

awesome.c

@@ -413,9 +413,10 @@ main(int argc, char **argv)
                                      XCB_CW_EVENT_MASK | XCB_CW_CURSOR,
                                      change_win_vals);
         ewmh_set_supported_hints(screen_nbr);
+    }
+
     /* call this to at least grab root window clicks */
     window_root_grabbuttons();
-    }
 
     /* scan existing windows */
     scan();