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/libcommon-cs/common_cs_vty.c b/openbsc/src/libcommon-cs/common_cs_vty.c
index 76336a1..bcc001d 100644
--- a/openbsc/src/libcommon-cs/common_cs_vty.c
+++ b/openbsc/src/libcommon-cs/common_cs_vty.c
@@ -88,7 +88,7 @@
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
 
-	bsc_replace_string(gsmnet, &gsmnet->name_short, argv[0]);
+	osmo_talloc_replace_string(gsmnet, &gsmnet->name_short, argv[0]);
 	return CMD_SUCCESS;
 }
 
@@ -99,7 +99,7 @@
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
 
-	bsc_replace_string(gsmnet, &gsmnet->name_long, argv[0]);
+	osmo_talloc_replace_string(gsmnet, &gsmnet->name_long, argv[0]);
 	return CMD_SUCCESS;
 }