HBSD: exclude /boot/efi with tar

The commit 6c1ebef2

 ("HBSD: Tell hbsd-update to skip /boot/efi")
is not enough to solve the problem encountered with tar.

Adding an exclude for /boot/efi.
Signed-off-by: Loic <loic.f@hardenedbsd.org>
Reported-by:	@PKraszewski and @zsalab
issue:		#43
MFC-to:		13-STABLE
MFC-to:		12-STABLE
(cherry picked from commit 781c18cf)

usr.sbin/hbsd-update/hbsd-update

@@ -661,6 +661,7 @@ apply_base() {
 	${TAR} -xpf ${tmpdir}/base.txz \
 		-X ${tmpdir}/skip.txt \
 		--exclude ./boot \
+		--exclude ./boot/efi \
 		-C ${mountpoint}
 	res=${?}
 	if [ ${res} -gt 0 ]; then
@@ -669,7 +670,7 @@ apply_base() {
 
 	boottmp=$(env TMPDIR=${tmpdir} ${MKTEMP} -d)
 	[ ! -d ${mountpoint}/boot ] && mkdir ${mountpoint}/boot
-	${TAR} -xpf ${tmpdir}/base.txz --include ./boot -C ${boottmp}
+	${TAR} -xpf ${tmpdir}/base.txz --include ./boot --exclude ./boot/efi -C ${boottmp}
 	${TAR} -c -C ${boottmp}/boot -f - . | \
 		(cd ${mountpoint}/boot; ${TAR} -xpf -)
 	res=${?}