libbsm: Rename package to audit-lib

This is part of audit, so use the new LIB_PACKAGE feature to name the
package audit-lib, rather than libbsm.

MFC after:	1 day
Reviewed by:	bapt
Sponsored by:	https://www.patreon.com/bsdivy
Differential Revision:	https://reviews.freebsd.org/D52789

lib/libbsm/Makefile

@@ -1,9 +1,8 @@
-#
-#
+PACKAGE=	audit
+LIB_PACKAGE=
 
-PACKAGE=	lib${LIB}
-OPENBSMDIR=		${SRCTOP}/contrib/openbsm
-_LIBBSMDIR=		${OPENBSMDIR}/libbsm
+OPENBSMDIR=	${SRCTOP}/contrib/openbsm
+_LIBBSMDIR=	${OPENBSMDIR}/libbsm
 
 LIB=		bsm
 SHLIB_MAJOR=	3