tests: make update_exp: build check_PROGRAMS first

Make test development a bit more convenient.

Change-Id: Ic053aa3ab7485176b58eab6ebb4835cfbe6b8260
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 63d94f0..08cdc17 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -194,7 +194,7 @@
 
 TESTSUITE = $(srcdir)/testsuite
 
-update_exp:
+update_exp: $(check_PROGRAMS)
 	rlcmac/RLCMACTest \
 		>$(srcdir)/rlcmac/RLCMACTest.ok \
 		2>$(srcdir)/rlcmac/RLCMACTest.err