The debian-bootstrap image doesn't choose a default architecture and
distribution version, instead the user has to set both DEB_ARCH and
DEB_TYPE in the environment. Print a reasonably helpful message if
either of them isn't set instead of complaining about "qemu-" being
missing or erroring out because we cannot cd to the mirror URL.
Signed-off-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Message-Id: <1473192351-601-5-git-send-email-silbe@linux.vnet.ibm.com>
Signed-off-by: NFam Zheng <famz@redhat.com>