package/bwm-ng: fix build failures with gcc-5

Bumping to the latest release, for 0.6 -> 0.6.1 to fix gcc-5 build
failures due to incorrect definitions of 'static' functions.

The project also has a new home.

Fixes:
    http://autobuild.buildroot.org/results/546/546b332cf95a48412d88add2feec2ffd4712857c/
    http://autobuild.buildroot.org/results/751/751797f3b97839f69626682ce81dca9bcb2cff22/


    ...

[Thomas: keep only the locally calculated sha256 hash, and do not
mention the commented SF.net hash, since SF.net is no longer the
official upstream location.]

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>