drop msc_compl_l3() return value

msc_compl_l3() always returns MSC_CONN_ACCEPT, because the conn FSM handles (or
should handle) all reject cases. The accept/reject return value is a legacy
from libbsc internally passing a conn over to libmsc, in osmo-nitb.

Drop enum msc_compl_l3_rc.
Change msc_compl_l3_rc() to return void.
Change all callers to always act like for acceptance, as they always did anyway.
Drop some local variables now no longer needed.
Adjust the comment to msc_compl_l3().
Drop a bunch of #if-0'd code from msc_compl_l3().

Change-Id: I759d15f4e820d5fc16397ed7210ce92308e52a09
diff --git a/src/libmsc/osmo_msc.c b/src/libmsc/osmo_msc.c
index 88a3dbb..05ac845 100644
--- a/src/libmsc/osmo_msc.c
+++ b/src/libmsc/osmo_msc.c
@@ -87,37 +87,15 @@
 		gsm411_sapi_n_reject(conn);
 }
 
-/* receive a Level 3 Complete message and return MSC_CONN_ACCEPT or
- * MSC_CONN_REJECT */
-int msc_compl_l3(struct gsm_subscriber_connection *conn,
-		 struct msgb *msg, uint16_t chosen_channel)
+/* receive a Level 3 Complete message.
+ * Ownership of the conn is completely passed to the conn FSM, i.e. for both acceptance and rejection,
+ * the conn FSM shall decide when to release this conn. It may already be discarded before this exits. */
+void msc_compl_l3(struct gsm_subscriber_connection *conn,
+		  struct msgb *msg, uint16_t chosen_channel)
 {
 	msc_subscr_conn_get(conn, MSC_CONN_USE_COMPL_L3);
 	gsm0408_dispatch(conn, msg);
-
 	msc_subscr_conn_put(conn, MSC_CONN_USE_COMPL_L3);
-
-	/* Always return acceptance, because even if the conn was not accepted,
-	 * we assumed ownership of it and the caller shall not interfere with
-	 * that. We may even already have discarded the conn. */
-	return MSC_CONN_ACCEPT;
-
-#if 0
-	/*
-	 * If this is a silent call we want the channel to remain open as long as
-	 * possible and this is why we accept this connection regardless of any
-	 * pending transaction or ongoing operation.
-	 */
-	if (conn->silent_call)
-		return MSC_CONN_ACCEPT;
-	if (conn->loc_operation || conn->sec_operation || conn->anch_operation)
-		return MSC_CONN_ACCEPT;
-	if (trans_has_conn(conn))
-		return MSC_CONN_ACCEPT;
-
-	LOGP(DRR, LOGL_INFO, "MSC Complete L3: Rejecting connection.\n");
-	return MSC_CONN_REJECT;
-#endif
 }
 
 /* Receive a DTAP message from BSC */