sh: install hard link with same mode as target

Previously when using NO_ROOT we recorded a METALOG entry for the
/.profile hard link with a different mode than the link target, which is
not permitted.

Reviewed by:	bapt
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D37476

bin/sh/Makefile

@@ -68,6 +68,7 @@ SUBDIR.${MK_TESTS}+= tests
 beforeinstallconfig:
 	rm -f ${DESTDIR}/.profile
 
+LINKMODE=${CONFMODE}
 afterinstallconfig:
 	${INSTALL_LINK} ${TAG_ARGS} ${DESTDIR}/root/.profile ${DESTDIR}/.profile