fix Makefile chmod (644)
replace MD5SUM with HASH
add PKG_MIRROR_HASH when PKG_SOURCE_PROTO:=git

(PKG_SOURCE_PROTO:=svn tarballs are not reproducible for now)

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Signed-off-by: Nicolas Thill <nico@openwrt.org>

Signed-off-by: Ian Leonard <antonlacon@gmail.com>

libnetfilter_acct is a userspace library providing a programming interface
(API) to the extended accounting infrastructure.

Signed-off-by: Nicolas Thill <nico@openwrt.org>