Bug 697027 - 3 - minor memory leaks found by Valgrind + TET

https://bugzilla.redhat.com/show_bug.cgi?id=697027

Description: Previous commit fe9b6a6bab32353f55a6ce2123f7df6b72a9a5a7
failed to remove unnecessary 3 slapi_counter_destroy calls.

ldap/servers/slapd/back-ldbm/cache.c

@@ -652,9 +652,6 @@ static void erase_cache(struct cache *cache, int type)
 #ifdef UUIDCACHE_ON 
     slapi_ch_free((void **)&cache->c_uuidtable);
 #endif
-    slapi_counter_destroy(&cache->c_cursize);
-    slapi_counter_destroy(&cache->c_hits);
-    slapi_counter_destroy(&cache->c_tries);
 }
 
 /* to be used on shutdown or when destroying a backend instance */