logging: Make sure to install standard "end" command in VTY node

When you are in the config-log VTY node, you expect "end" to work
like in any other sub-node of config.
diff --git a/include/osmocom/vty/command.h b/include/osmocom/vty/command.h
index caafdeb..8fbb482 100644
--- a/include/osmocom/vty/command.h
+++ b/include/osmocom/vty/command.h
@@ -361,6 +361,7 @@
 extern struct cmd_element config_exit_cmd;
 extern struct cmd_element config_help_cmd;
 extern struct cmd_element config_list_cmd;
+extern struct cmd_element config_end_cmd;
 char *host_config_file();
 void host_config_set(const char *);
 
diff --git a/src/vty/logging_vty.c b/src/vty/logging_vty.c
index 971ec3b..d473f12 100644
--- a/src/vty/logging_vty.c
+++ b/src/vty/logging_vty.c
@@ -592,6 +592,8 @@
 	install_element_ve(&show_logging_vty_cmd);
 
 	install_node(&cfg_log_node, config_write_log);
+	install_default(CFG_LOG_NODE);
+	install_element(CFG_LOG_NODE, &config_end_cmd);
 	install_element(CFG_LOG_NODE, &logging_fltr_all_cmd);
 	install_element(CFG_LOG_NODE, &logging_use_clr_cmd);
 	install_element(CFG_LOG_NODE, &logging_prnt_timestamp_cmd);