projects/RPi/patches/linux: update RPi support patch

Signed-off-by: Stephan Raue <stephan@openelec.tv>
gnutls: update to gnutls-3.2.15

Signed-off-by: Stephan Raue <stephan@openelec.tv>
inputproto: update to inputproto-2.3.1

Signed-off-by: Stephan Raue <stephan@openelec.tv>
scripts/image: fix etc/os-release