* Ensure that there is always at least one primary partition after autopartitioning. An existing primary partition on the disk satisfies this, as does a recipe partition explicitly marked $primary{ }; if neither of those exists, then arbitrarily promote the first recipe partition to be a primary partition. * Remove explicit $primary{ } specifiers from standard recipes. We only need them to be primary if no other primary partitions exist already. * Relax auto-resize constraints now that a primary partition is not unconditionally required; this will allow auto-resize partitioning on systems that already have three primary partitions (LP: #134950).