vty: Use vty_install_default() instead of bsc_install_default()

Remove ournode_exit_cmd, ournode_end_cmd, and bsc_install_default()
since this functionality is provided by the current libosmocore.

Replace calls to bsc_install_default() by call to
vty_install_default() with the following semantic patch:

    @rule1@
    expression N;
    @@
    - bsc_install_default(N);
    + vty_install_default(N);

Ticket: OW#952
Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/libmgcp/mgcp_vty.c b/openbsc/src/libmgcp/mgcp_vty.c
index 9421f4f..3c239d8 100644
--- a/openbsc/src/libmgcp/mgcp_vty.c
+++ b/openbsc/src/libmgcp/mgcp_vty.c
@@ -786,7 +786,7 @@
 	install_element(CONFIG_NODE, &cfg_mgcp_cmd);
 	install_node(&mgcp_node, config_write_mgcp);
 
-	bsc_install_default(MGCP_NODE);
+	vty_install_default(MGCP_NODE);
 	install_element(MGCP_NODE, &cfg_mgcp_local_ip_cmd);
 	install_element(MGCP_NODE, &cfg_mgcp_bts_ip_cmd);
 	install_element(MGCP_NODE, &cfg_mgcp_bind_ip_cmd);
@@ -818,7 +818,7 @@
 
 	install_element(MGCP_NODE, &cfg_mgcp_trunk_cmd);
 	install_node(&trunk_node, config_write_trunk);
-	bsc_install_default(TRUNK_NODE);
+	vty_install_default(TRUNK_NODE);
 	install_element(TRUNK_NODE, &cfg_trunk_payload_number_cmd);
 	install_element(TRUNK_NODE, &cfg_trunk_payload_name_cmd);
 	install_element(TRUNK_NODE, &cfg_trunk_payload_number_cmd_old);