refactor: move local address resolution into start_listen_socket

sslh-conf.c

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Sat Nov  7 09:23:57 2020. 
+ * on Sat Nov  7 09:31:10 2020. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2019  Yves Rutschle
@@ -863,9 +863,9 @@ static struct config_desc table_sslhcfg[] = {
             /* offset_present */ 0,
             /* size */          sizeof(char*), 
             /* array_type */    -1,
-            /* mandatory */     1, 
+            /* mandatory */     0, 
             /* optional */      0, 
-            /* default_val*/    .default_val.def_string = NULL 
+            /* default_val*/    .default_val.def_string = "" 
         },
 
         {