rng-egd: remove redundant free

We didn't set default chr_name, the free is redundant.
Signed-off-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

backends/rng-egd.c

@@ -167,7 +167,6 @@ 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);
     }
 }