FileCache getIfPresent doesn't update cache hit/miss counters

FileCache.getIfPresent bypasses cache access if key is not in cache and CacheStats for "DataStore-DownloadCache" MBean will always have 100% hit rate even when Blobs will be downloaded from the BlobStore backend by AbstractSharedCachingDataStore because of the miss in the cache.

I suggest the following change:
FileCache.getIfPresent to call CacheLIRS.getIfPresent which will update the cache stats (miss and hit counters).