Revert "Create the boot partition before we try and mark it as active"

This reverts commit 66571e5c7c2b4d2637f6d281e52b0e0a9e941de0.
Revert "Replace usage of fdisk with gpart."

This reverts commit 1915b6c860f058547aa75734a3523aaa23256c60.
Make fdisk use the non-nop versions of the devices.