tests: use -no-install libtool flag to avoid ./lt-* scripts

This ensures that the rpath of the generated binaries is set to use only
the just-compiled so-files and not any system-wide installed libraries
while avoiding the ugly shell script wrapper.

Change-Id: Idd458471069ef8912704cc7602c6e8c71c0b62be
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c8b8996..8ee91bb 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -1,6 +1,6 @@
 AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
 AM_CFLAGS=-Wall -g $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(COVERAGE_CFLAGS)
-AM_LDFLAGS = $(COVERAGE_LDFLAGS)
+AM_LDFLAGS = $(COVERAGE_LDFLAGS) -no-install
 
 check_PROGRAMS = e1inp_ipa_bsc_test	\
 		  e1inp_ipa_bts_test	\