fix 'make vty-test' for --disable-external-tests --enable-gb

Change-Id: I80ac270bfb563a769a7746d8fbceac09e267ce03
diff --git a/utils/Makefile.am b/utils/Makefile.am
index c068ee2..8937ad9 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -31,6 +31,7 @@
 SUBDIRS = \
 	osmo-stat-dummy \
 	$(NULL)
+endif
 
 if ENABLE_GB
 noinst_PROGRAMS += osmo-ns-dummy
@@ -41,4 +42,3 @@
 			$(top_builddir)/src/ctrl/libosmoctrl.la \
 			$(NULL)
 endif
-endif