rsync is used in the infrastructure, mostly for the per-package infra,
and for the override-srcdir mechanism, but also to build the manual.
As such, it is not optional but mandatory, and already listed so.
Drop the reference to rsync from the list of optional packages.
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
