patch: fix of configuration file generation

[Andreas.Eversberg]

this patches fixes the generation of the config file.
 
after saving of configuration, no location update was possible anymore.

it is self explaining...
 
diff --git a/openbsc/src/vty_interface.c b/openbsc/src/vty_interface.c
index 9aa9706..c6e60c0 100644
--- a/openbsc/src/vty_interface.c
+++ b/openbsc/src/vty_interface.c
@@ -784,7 +784,7 @@ DEFUN(cfg_net_encryption,
       "encryption a5 (0|1|2)",
       "Enable or disable encryption (A5) for this network\n")
 {
-	gsmnet->auth_policy = atoi(argv[0]);
+	gsmnet->a5_encryption = atoi(argv[0]);
 
 	return CMD_SUCCESS;
 }