rename gprs_gsup_client.h to gsup_client.h

This is in preparation for moving gsup to libcommon, which is in turn
preparation for libvlr.

Related: OS#1592
Change-Id: I9c95d00f1a9420887a44c938b1d0ee3e20586f4c
diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index 16eb6c9..b4bcaf6 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -25,7 +25,7 @@
 #include <openbsc/debug.h>
 #include <openbsc/gsm_subscriber.h>
 #include <osmocom/gsm/gsup.h>
-#include <openbsc/gprs_gsup_client.h>
+#include <openbsc/gsup_client.h>
 #include <openbsc/gprs_utils.h>
 #include <openbsc/gprs_gb_parse.h>