cosmetic: vlr: rename auth_tuple_max_use_count to _reuse_

The name auth_tuple_max_use_count suggests that if I want to use each auth
tuple exactly once, I need to set it to 1. Curiously, so far you need to set
to intended uses - 1.

Reflect this in its name by renaming to auth_tuple_max_reuse_count.

I first considered to not rename but change the if-conditions so that == 1
means each tuple is used once, and upon struct vlr allocation, set the default
to 1. That would also logically entail that setting to 0 means to re-use
vectors infinitely often, like now a value < 0 does. That means, when
allocating a vlr struct zeroed out, we would by default have the most
dangerous/unsafe configuration. It's no problem to set a default to 1 upon
allocation, but by renaming the variable instead, we get safer alloc-zero
behavior and don't need to change any conditionals in the code (even though the
patch ends up considerably larger from all the renaming).

Change-Id: I0b036cae1536d5d6fb2304f837ed1a6c3713be55
diff --git a/tests/msc_vlr/msc_vlr_test_hlr_reject.c b/tests/msc_vlr/msc_vlr_test_hlr_reject.c
index 095da81..6cf4afc 100644
--- a/tests/msc_vlr/msc_vlr_test_hlr_reject.c
+++ b/tests/msc_vlr/msc_vlr_test_hlr_reject.c
@@ -84,7 +84,7 @@
 
 	net->authentication_required = true;
 	net->vlr->cfg.auth_reuse_old_sets_on_error = false;
-	net->vlr->cfg.auth_tuple_max_use_count = 0;
+	net->vlr->cfg.auth_tuple_max_reuse_count = 0;
 
 	BTW("Submit a used auth tuple in the VLR");
 	btw("Location Update request causes a GSUP Send Auth Info request to HLR");
@@ -171,7 +171,7 @@
 
 	net->authentication_required = true;
 	net->vlr->cfg.auth_reuse_old_sets_on_error = true;
-	net->vlr->cfg.auth_tuple_max_use_count = 0;
+	net->vlr->cfg.auth_tuple_max_reuse_count = 0;
 
 	BTW("Submit a used auth tuple in the VLR");
 	btw("Location Update request causes a GSUP Send Auth Info request to HLR");
@@ -256,7 +256,7 @@
 
 	net->authentication_required = true;
 	net->vlr->cfg.auth_reuse_old_sets_on_error = true;
-	net->vlr->cfg.auth_tuple_max_use_count = 0;
+	net->vlr->cfg.auth_tuple_max_reuse_count = 0;
 
 	btw("Location Update request causes a GSUP Send Auth Info request to HLR");
 	lu_result_sent = RES_NONE;
@@ -291,7 +291,7 @@
 
 	net->authentication_required = true;
 	net->vlr->cfg.auth_reuse_old_sets_on_error = true;
-	net->vlr->cfg.auth_tuple_max_use_count = 0;
+	net->vlr->cfg.auth_tuple_max_reuse_count = 0;
 
 	BTW("Submit a used auth tuple in the VLR");
 	btw("Location Update request causes a GSUP Send Auth Info request to HLR");