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>

Alarm Pinger (apinger) is a little tool which monitors various IP devices by
simple ICMP echo requests. There are various other tools, that can do this,
but most of them are shell or perl scripts, spawning many processes, thus much
CPU-expensive, especially when one wants continuous monitoring and fast
response on target failure.

Signed-off-by: Alex Samorukov <samm@os2.kiev.ua>