consistency: only in process_change (called by process_rollback & process_unikernel_update) Albatross.manifest_devices_match is invoked

[hannesm]

This is not done during a "normal" deploy (i.e. unikernel_create). The normal deploy is also missing a "force" checkbox to do a force-create.

But with #73 in mind and streaming, we'll have to revise that manifest_devices_match in some way anyways, storing another bigarray with the unikernel binary in memory is not a good idea (we need a streaming interface for Solo5_elftool, where it doesn't need to have its hands on the entire binary).