vty: fix memleak in host_config_set()

Not only we call this function from vty_read_config_file(), but
also from config_write_file_cmd.  Thus we leak memory when doing
'write file FILE' in the VTY.

Change-Id: I356818aae3addab6db39de9a625453b7435b7cc1
---
M src/vty/command.c
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/vty/command.c b/src/vty/command.c
index a3e0e36..1719690 100644
--- a/src/vty/command.c
+++ b/src/vty/command.c
@@ -4297,7 +4297,7 @@
 /* Set config filename.  Called from vty.c */
 void host_config_set(const char *filename)
 {
-	host.config = talloc_strdup(tall_vty_cmd_ctx, filename);
+	osmo_talloc_replace_string(tall_vty_cmd_ctx, &host.config, filename);
 }
 
 const char *host_config_file(void)

