main: Mark crypto_model key read only

... to be in align with crypto_cypher and crypto_hash.

Reload (corosync-cfgtool -R) works without any problem and changing of
key is not supported anyway,

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>

exec/main.c

@@ -1045,6 +1045,7 @@ static void set_icmap_ro_keys_flag (void)
 	 */
 	icmap_set_ro_access("totem.crypto_cipher", CS_FALSE, CS_TRUE);
 	icmap_set_ro_access("totem.crypto_hash", CS_FALSE, CS_TRUE);
+	icmap_set_ro_access("totem.crypto_model", CS_FALSE, CS_TRUE);
 	icmap_set_ro_access("totem.keyfile", CS_FALSE, CS_TRUE);
 	icmap_set_ro_access("totem.key", CS_FALSE, CS_TRUE);
 	icmap_set_ro_access("totem.secauth", CS_FALSE, CS_TRUE);