libmsc: Use RAND_bytes when choosing a tmsi

Require openssl version to be >= 0.9.5 because we rely on the RAND_bytes
return value.

[hfreyther: Add cast to uint8_t*]
diff --git a/openbsc/src/osmo-nitb/Makefile.am b/openbsc/src/osmo-nitb/Makefile.am
index 57a9284..d3b97f8 100644
--- a/openbsc/src/osmo-nitb/Makefile.am
+++ b/openbsc/src/osmo-nitb/Makefile.am
@@ -16,4 +16,4 @@
 		$(top_builddir)/src/libcommon/libcommon.a \
 		-ldbi $(LIBCRYPT)				   \
 		$(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOCORE_LIBS)  \
-		$(LIBOSMOCTRL_LIBS) $(LIBOSMOABIS_LIBS) $(LIBSMPP34_LIBS)
+		$(LIBOSMOCTRL_LIBS) $(LIBOSMOABIS_LIBS) $(LIBSMPP34_LIBS) $(LIBCRYPTO_LIBS)