Add missing step in installing into Ubuntu
Add missing step in installing into Ubuntu

Signed-off-by: cheesiong.lee <cheesiong.lee@prophetstor.com>

Closes: #1458
Approved by: rhatdan

nalind/buildah,TomSweeneyRedHat/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,nalind/buildah,nalind/buildah-1,rhatdan/buildah,rhatdan/buildah,nalind/buildah-1,projectatomic/buildah,nalind/buildah-1,TomSweeneyRedHat/buildah,projectatomic/buildah,rhatdan/buildah