Revert "rng-egd: remove redundant free"

This reverts commit 5e490b6a.

Cc: qemu-stable@nongnu.org
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

backends/rng-egd.c

@@ -169,6 +169,7 @@ static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp)
     if (b->opened) {
         error_set(errp, QERR_PERMISSION_DENIED);
     } else {
+        g_free(s->chr_name);
         s->chr_name = g_strdup(value);
     }
 }