[SAC] projectsVM: rsync reniced to 10

[Markus Neteler]

Hi SAC,

FYI

since some openlayers rsync jobs almost killed the projVM, I have
generally reniced rsync to 10, i.e. modified the related value in
/etc/default/rsync
and restarted the daemon.

Now the machine is responsive again.

cheers
Markus