vmdebootstrap leaves loop0p1 around
On arm01 loop0p1 is left around after an image build so that other builds afterwards fail like
device-mapper: reload ioctl on loop0p2p1 failed: Device or resource busy create/reload failed on loop0p2p1
dmsetup remove loop0p1 works around this (which we currently do in /etc/cron.hourly/work-around-vmdebootstrap).
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