tests: Introduce running tests with GNU autotest in OpenBSC

The quality of the tests is of different value but it is good to
get started and improve from here.
diff --git a/openbsc/tests/db/Makefile.am b/openbsc/tests/db/Makefile.am
index aab2cd6..f0d65f8 100644
--- a/openbsc/tests/db/Makefile.am
+++ b/openbsc/tests/db/Makefile.am
@@ -2,6 +2,8 @@
 AM_CFLAGS=-Wall -ggdb3 $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
 AM_LDFLAGS = $(COVERAGE_LDFLAGS)
 
+EXTRA_DIST = db_test.ok
+
 noinst_PROGRAMS = db_test
 
 db_test_SOURCES = db_test.c