linux: update to linux-3.15-rc3
linux (3.15): mceusb xhci fix

source: https://patchwork.linuxtv.org/patch/23780/

fixed minor if (( => if ( typos
fixed mce_dbg => dev_dbg
scripts/image: update /etc/os-release

Signed-off-by: Stephan Raue <stephan@openelec.tv>
Fixed a typo

Conflicts:
	projects/ATV/options
	projects/Cuboxi/options
	projects/RPi/options
	projects/Virtual/options
util-linux: update to util-linux-2.24.2

Signed-off-by: Stephan Raue <stephan@openelec.tv>
xbmc: add upstream patch, this fixes #3148, thanks to 'JoseAntonioRodriguez' and 'fernetmenta'

Signed-off-by: Stephan Raue <stephan@openelec.tv>
tools/mkpkg: move mkpkg_xbmc script to mkpkg_xbmc-gotham, add mkpkg_xbmc which checks out xbmc master

Signed-off-by: Stephan Raue <stephan@openelec.tv>