buildroot

erlang: bump to version 17.3

Erlang/OTP 17.3 is a service release on the 17 track with mostly bug
fixes, but it does contain a number of new features and characteristics
improvements as well.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>