Call ms_store->get_ms() with GSM_RESERVED_TMSI instead of 0

That's the special value checked in the implementation of get_ms() to
skip lookups based on TLLI.
This should save some cicles trying to match TLLI 0.

Change-Id: I364d238ff8a82abb14281140fe18b273c0e8f541
diff --git a/tests/ms/MsTest.cpp b/tests/ms/MsTest.cpp
index 2ff2fc2..cbafee9 100644
--- a/tests/ms/MsTest.cpp
+++ b/tests/ms/MsTest.cpp
@@ -416,10 +416,10 @@
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(ms_tlli(ms) == tlli + 0);
 
-	ms_tmp = store.get_ms(0, 0, imsi1);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi1);
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(strcmp(ms_imsi(ms), imsi1) == 0);
-	ms_tmp = store.get_ms(0, 0, imsi2);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi2);
 	OSMO_ASSERT(ms_tmp == NULL);
 
 	ms = prepare_ms(&store, tlli + 1, GPRS_RLCMAC_UL_TBF);
@@ -432,10 +432,10 @@
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(ms_tlli(ms) == tlli + 1);
 
-	ms_tmp = store.get_ms(0, 0, imsi1);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi1);
 	OSMO_ASSERT(ms_tmp != NULL);
 	OSMO_ASSERT(ms_tmp != ms);
-	ms_tmp = store.get_ms(0, 0, imsi2);
+	ms_tmp = store.get_ms(GSM_RESERVED_TMSI, GSM_RESERVED_TMSI, imsi2);
 	OSMO_ASSERT(ms == ms_tmp);
 	OSMO_ASSERT(strcmp(ms_imsi(ms), imsi2) == 0);