eliminate global.cookie and the cache-invalidation which it enabled

src/kernel/config.c

@@ -1006,15 +1006,12 @@ void set_param(struct param **p, const char *key, const char *value)
             const char * kv = (const char *)match;
             size_t vlen = strlen(kv + klen) + 1;
             cb_erase(&par->cb, kv, klen + vlen);
-            ++global.cookie;
         }
     }
     if (value) {
         char data[512];
         size_t sz = pack_keyval(key, value, data, sizeof(data));
-        if (cb_insert(&par->cb, data, sz) == CB_SUCCESS) {
+        cb_insert(&par->cb, data, sz);
-            ++global.cookie;
-        }
     }
 }
 
@@ -1631,7 +1628,6 @@ void free_gamedata(void)
     while (global.attribs) {
         a_remove(&global.attribs, global.attribs);
     }
-    ++global.cookie;              /* readgame() already does this, but sjust in case */
 }
 
 const char * game_name(void) {

src/kernel/config.h

@@ -205,9 +205,6 @@ struct param;
                 const struct race * rc, int in_turn);
             int(*maintenance) (const struct unit * u);
         } functions;
-        /* the following are some cached values, because get_param can be slow.
-         * you should almost never need to touch them */
-        int cookie;
     } settings;
 
     typedef struct helpmode {

src/kernel/save.c

@@ -1449,7 +1449,6 @@ int readgame(const char *filename, bool backup)
     global.data_turn = turn;
     log_debug(" - reading turn %d\n", turn);
     rng_init(turn);
-    ++global.cookie;
     READ_INT(&store, &nread);          /* max_unique_id = ignore */
     READ_INT(&store, &nextborder);