ms: Get rid of ms->delay field

Simply apply the content of the configured timer when the MS goes idle.
Having that field is convenient to do tricky stuff in unit tests, but
makes the main osmo-pcu app more complex for no good enough reason.

Change-Id: I8d44318b37b6605afd84db8ccec0d75e6db293b9
diff --git a/src/bts.cpp b/src/bts.cpp
index 4cbe68e..d4bb35f 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -241,11 +241,8 @@
 static int bts_talloc_destructor(struct gprs_rlcmac_bts* bts)
 {
 	struct GprsMs *ms;
-	while ((ms = llist_first_entry_or_null(&bts->ms_list, struct GprsMs, list))) {
-		ms_set_timeout(ms, 0);
-		bts_stat_item_dec(bts, STAT_MS_PRESENT);
+	while ((ms = llist_first_entry_or_null(&bts->ms_list, struct GprsMs, list)))
 		talloc_free(ms);
-	}
 
 	gprs_bssgp_destroy(bts);