awful.menu: handling with strings

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/awful/menu.lua.in

@@ -88,6 +88,9 @@ local function load_theme(a, b)
                  fallback.menu_height or 16
     ret.width = a.width or b.menu_width or b.width or
                 fallback.menu_width or 100
+    for _, prop in ipairs({"width", "height", "menu_width"}) do
+        if type(ret[prop]) ~= "number" then ret[prop] = tonumber(ret[prop]) end
+    end
     return ret
 end