don't re-implement osmo_talloc_replace_string()

osmo_talloc_replace_string() was introducd into libosmocore in 2014, see
commit f3c7e85d05f7b2b7bf093162b776f71b2bc6420d

There's no reason for us to re-implement this as bsc_replace_string
here.

Change-Id: I6d2fcaabbc74730f6f491a2b2d5c784ccafc6602
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_main.c b/openbsc/src/osmo-bsc/osmo_bsc_main.c
index 2f0b96d..ee094d6 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_main.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_main.c
@@ -253,7 +253,7 @@
 
 	data = bsc_gsmnet->bsc_data;
 	if (rf_ctrl)
-		bsc_replace_string(data, &data->rf_ctrl_name, rf_ctrl);
+		osmo_talloc_replace_string(data, &data->rf_ctrl_name, rf_ctrl);
 
 	data->rf_ctrl = osmo_bsc_rf_create(data->rf_ctrl_name, bsc_gsmnet);
 	if (!data->rf_ctrl) {