Explicitly name target volume for Qubes staging install
Explicitly name target volume for Qubes staging install

Originally included by @joshuathayer, but aggressive concision edits on
my part removed it. During review, @emkll requested the additional
clarity, which sounds well warranted, so adding back.

ehartsuyker/securedrop,conorsch/securedrop,heartsucker/securedrop,ehartsuyker/securedrop,conorsch/securedrop,heartsucker/securedrop,conorsch/securedrop,heartsucker/securedrop,heartsucker/securedrop,conorsch/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,conorsch/securedrop,heartsucker/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop