Fix cache issue

[rvm-peercode]

In some cases, the cache layer would return values even if those values should not have been returned because their tags had been invalidated. This could happen if you would call $this->cache->getCacheItem($cacheKey); without wrapping that call inside an if block if ($this->cache->hasItem($cacheKey)) { }

Now getCacheItem() will no longer return a result if the item is invalidated, so it is no longer necessary to check with hasItem().