README.install: add '--artifacts' option to sample cubeit call
README.install: add '--artifacts' option to sample cubeit call

When the usb-creator.sh script was renamed to cubeit the options to
invoke installer creation also changed. Previously this was just an
ordered option but now is prefixed.

Signed-off-by: Mark Asselstine <9d979f2c41783077c213bce515ff7ad668691d2c@windriver.com>
Signed-off-by: Bruce Ashfield <284cc737d174a260eec2a2a6324a304f84b1ae0f@windriver.com>

jwessel/meta-overc,OverC/meta-overc,WindRiver-OpenSourceLabs/meta-overc,jwessel/meta-overc,mufeng/meta-overc,OverC/meta-overc,mufeng/meta-overc,WindRiver-OpenSourceLabs/meta-overc,OverC/meta-overc,WindRiver-OpenSourceLabs/meta-overc,OverC/meta-overc,mufeng/meta-overc,OverC/meta-overc,masselstine/meta-overc,masselstine/meta-overc,masselstine/meta-overc,masselstine/meta-overc,jwessel/meta-overc,OverC/meta-overc