I also had this problem, so I was happy to see it was already fixed. Though i noticed on php.net that another php beta release should be available in a few days, I was hoping that this an interim version (5.5.0~beta2-2 perhaps?) could be uploaded already, because the owncloud 5.0.3 package was uploaded yesterday and it seems to require gd to work. So this is no longer a matter of merely having persistent error notifications.
If this is not possible, I will just have to wait a little while longer (it's all from experimental anyway, so it's to be expected). It might still be useful to communicate this to the owncloud maintainers though.
