migrate-nilrt: error out if packages are not found
migrate-nilrt: error out if packages are not found

if ni_migrate_target does not find needed packages for migration it
prints an error and exists, it does not reboot because with an
incomplete provisioning install it risks bricking a target.

(Also add clean up logic in case of errors.)

Signed-off-by: Ioan-Adrian Ratiu <7ec73abcfe099fc5574c01312b62768070c80980@ni.com>

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt