getrusage is used in a number of places throughout the qemu codebase
(notably, in crypto/pbkdf.c).  Without this syscall being whitelisted,
qemu ends up getting killed by the kernel whenever you try to connect to
a VNC console.

Signed-off-by: Brian Rak <brak@gameservers.com>
Acked-by: Eduardo Otubo <eduardo.otubo@profitbricks.com>