Ticket 47899: Fix slapi_td_plugin_lock_init prototype

Description: FreeIPA compilation gives a GCC warning in a 389-ds header:
warning: function declaration isn't a prototype
Fixing the warning as follows:
  -int slapi_td_plugin_lock_init();
  +int slapi_td_plugin_lock_init(void);
Note: () takes any number of arguments, while (void) takes none.

ldap/servers/slapd/slapi-plugin.h

@@ -5582,7 +5582,7 @@ void slapi_td_get_val(int indexType, void **value);
 int slapi_td_dn_init(void);
 int slapi_td_set_dn(char *dn);
 void slapi_td_get_dn(char **dn);
-int slapi_td_plugin_lock_init();
+int slapi_td_plugin_lock_init(void);
 int slapi_td_set_plugin_locked(int *value);
 void slapi_td_get_plugin_locked(int **value);