ejabberd: Bump to version 17.11

* Adapt all patches.
* Use the new configure option enable-system-deps even though there is
  still a patch needed to correct includes.
* Disable graphics to not depends on X libraries. Disable also
  mod_avatar from the default loaded modules, since this module
  requires graphics enabled.

Signed-off-by: Johan Oudinet <johan.oudinet@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>