Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Turn loader GELI support in the boot loaders off by default as a
temporary workaround. This fixes zfs booting generally, but breaks all
GELI booting by default. Add note to UPDATING to this effect. When the
GELI issues are resolved, this will be reverted.

Move sys/boot to stand. Fix all references to new location

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