e17/comp: wait for first damage on win_show. 
e17/comp: wait for first damage on win_show. 

this fixes pixel garbage with many gtk menus.
are there any windows that dont create damage on show?


git-svn-id: 6ac5796aeae0cef97fb47bcc287d4ce899c6fa6e@57513 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

jordemort/e17,jordemort/e17,jordemort/e17