Fix ”make distcheck“ errors

Reflect the rewrite of update-alternatives in commit
cab5af04fadcd939a7becd5fcb25dcfb7bc121dd and the addition of
scripts/t/origin in commit 2d4fd627d4286dc42006fb486040209d4e021b9f.

po/POTFILES.in

@@ -68,6 +68,6 @@ dpkg-split/queue.c
 dpkg-split/split.c
 
 utils/start-stop-daemon.c
+utils/update-alternatives.c
 
 scripts/dpkg-divert.pl
-scripts/update-alternatives.pl

scripts/Makefile.am

@@ -27,7 +27,6 @@ changelog_SCRIPTS = \
 	changelog/debian
 
 EXTRA_DIST = \
-	README.alternatives \
 	dpkg-architecture.pl \
 	dpkg-buildflags.pl \
 	dpkg-buildpackage.pl \
@@ -222,7 +221,10 @@ test_data = \
 	t/910_merge_changelogs/ch-merged \
 	t/910_merge_changelogs/ch-merged-basic \
 	t/910_merge_changelogs/ch-merged-pr \
-	t/910_merge_changelogs/ch-merged-pr-basic
+	t/910_merge_changelogs/ch-merged-pr-basic \
+	t/origins/debian \
+	t/origins/default \
+	t/origins/ubuntu
 
 clean-local:
 	rm -fr man

utils/Makefile.am

@@ -10,6 +10,13 @@ AM_CPPFLAGS = \
 	-I$(top_builddir) \
 	-I$(top_srcdir)/lib
 
+test_cases = \
+	t/100_update_alternatives.t
+
+EXTRA_DIST = \
+	README.alternatives \
+	$(test_cases)
+
 bin_PROGRAMS =
 
 if WITH_UPDATE_ALTERNATIVES