build-sys: add git-version-gen and test.sh to release package

Without this patch autoreconf, when done with release tarball, fails like
this:

$ autoreconf -f -i
sh: 1: build-aux/git-version-gen: not found
configure.ac:12: error: AC_INIT should be called with package and version arguments
/usr/share/aclocal-1.11/init.m4:26: AM_INIT_AUTOMAKE is expanded from...
configure.ac:12: the top level
autom4te: /usr/bin/m4 failed with exit status: 1
aclocal: /usr/bin/autom4te failed with exit status: 1
autoreconf: aclocal failed with exit status: 1

Further down the road tests start to fail after autoreconf.

make[4]: Leaving directory `/home/grohne/debian/dhcpd-pools-debian/tests'
make[3]: *** No rule to make target `../tests/test.sh', needed by `check-local'.  Stop.
make[3]: Leaving directory `/home/grohne/debian/dhcpd-pools-debian/tests'
make[2]: *** [check-am] Error 2
make[2]: Leaving directory `/home/grohne/debian/dhcpd-pools-debian/tests'
make[1]: *** [check-recursive] Error 1
make[1]: Leaving directory `/home/grohne/debian/dhcpd-pools-debian'

Which is a symptom of not having test.sh in distribution.

Reported-by: Helmut Grohne <h.grohne@cygnusnetworks.de>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

Makefile.am

@@ -3,5 +3,9 @@
 AUTOMAKE_OPTIONS = gnu
 ACLOCAL_AMFLAGS = -I m4
 
-EXTRA_DIST = m4/gnulib-cache.m4
+EXTRA_DIST = \
+	.tarball-version \
+	build-aux/git-version-gen \
+	m4/gnulib-cache.m4
+
 SUBDIRS = doc lib src man tests contrib

THANKS

@@ -25,3 +25,4 @@ Enno Gr
 Ryan Malek
 Cheer Xiao
 Gilles Bouthenot
+Helmut Grohne

tests/Makefile.am

@@ -11,6 +11,7 @@ EXTRA_DIST = \
 	confs \
 	expected \
 	leases \
+	test.sh \
 	$(TESTS)
 
 TESTS_ENVIRONMENT = top_srcdir=$(top_srcdir) PATH=../src$(PATH_SEPARATOR)$$PATH