tests: Split ipv6 specific tests into a new test group

This way they can be easily disabled later on when IPv6 support is made
optional.

Change-Id: I3906dbf55ccf1650083398e08ac870add0bbdcef
diff --git a/tests/lib/Makefile.am b/tests/lib/Makefile.am
index 95d6901..ee46468 100644
--- a/tests/lib/Makefile.am
+++ b/tests/lib/Makefile.am
@@ -1,7 +1,11 @@
 AM_CFLAGS = -Wall -I$(top_srcdir)/include $(LIBOSMOCORE_CFLAGS) -g
 
-EXTRA_DIST = ippool_test.ok ippool_test.err \
-	     in46a_test.ok
+EXTRA_DIST = ippool_test.ok \
+	     ippool_test.err \
+	     ippool_v6_test.ok \
+	     ippool_v6_test.err \
+	     in46a_test.ok \
+	     in46a_v6_test.ok
 
 noinst_PROGRAMS = ippool_test in46a_test