Add linux spec description
Add linux spec description

Signed-off-by: Michael Crosby <951f4c7b5d47e32d0112c78d14a98eaa23e6b5ef@gmail.com>

LK4D4/specs,vbatts/specs,jonboulle/specs,zenlinTechnofreak/specs,vishh/specs,ujuc/specs,gao-feng/specs,mheon/specs,cloudfoundry-incubator/specs,laijs/specs,wking/opencontainer-specs,jhjeong-kr/specs,rootfs/specs,sladage/specs,wking/opencontainer-runtime-spec,wangkirin/specs,talwai/specs,kensipe/specs,hqhq/specs,haijunTan/specs,HardikDR/specs,dustymabe/specs,ChengTiesheng/specs,opencontainers/runtime-spec,runcom/specs,philips/specs,opencontainers/specs,marcosnils/specs,navidshaikh/specs,hqhq/runtime-spec