Remove the instances of :buttons(awful.button()).

Having buttons without an awful.util.table.join/gears.table.join
has never been officially documented to be supported. I hope there
isn't too many of those and they wont try to mix the new and old
API syntax, because that will totally break.

lib/awful/titlebar.lua

@@ -730,16 +730,20 @@ function titlebar.widget.button(c, name, selector, action)
     end
     ret.state = ""
     if action then
-        ret:buttons(abutton({ }, 1, nil, function()
-            ret.state = ""
-            update()
-            action(c, selector(c))
-        end))
+        ret.buttons = {
+            abutton({ }, 1, nil, function()
+                ret.state = ""
+                update()
+                action(c, selector(c))
+            end)
+        }
     else
-        ret:buttons(abutton({ }, 1, nil, function()
-            ret.state = ""
-            update()
-        end))
+        ret.buttons = {
+            abutton({ }, 1, nil, function()
+                ret.state = ""
+                update()
+            end)
+        }
     end
     ret:connect_signal("mouse::enter", function()
         ret.state = "hover"

lib/awful/tooltip.lua

@@ -212,7 +212,9 @@ function tooltip:get_wibox()
 
     -- Close the tooltip when clicking it.  This gets done on release, to not
     -- emit the release event on an underlying object, e.g. the titlebar icon.
-    wb:buttons(a_button({}, 1, nil, self.hide))
+    wb.buttons = {
+        a_button({}, 1, nil, self.hide)
+    }
 
     self._private.wibox = wb
 

lib/awful/widget/button.lua

@@ -46,8 +46,11 @@ function button.new(args)
         orig_set_image(self, img_release)
     end
     w:set_image(args.image)
-    w:buttons(abutton({}, 1, function () orig_set_image(w, img_press) end,
-                             function () orig_set_image(w, img_release) end))
+
+    w.buttons = {
+        abutton({}, 1, function () orig_set_image(w, img_press) end,
+                       function () orig_set_image(w, img_release) end)
+    }
 
     w:connect_signal("mouse::leave", function(self) orig_set_image(self, img_release) end)