sysvinit: Remove ${B} assignment

The VERSION variable is not set unless the
top level Makefile is used as the version is
derived from the Changelog.
If VERSION is not set, none of the binaries built
in the sysvinit recipe will have a valid version
output.
Before:
INIT: version  booting
After:
INIT: version 2.96 booting

Using the top level Makefile does not cause any
additional builds to occur.

Signed-off-by: Michael Gloff <mgloff@emacinc.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 10992ad4)
Signed-off-by: Steve Sakoman <steve@sakoman.com>