file.go: return the correct error message from load() when the cache at the given filePath has unexpected number of bucket chunks

Previously the error message was returning misleading information,
which didn't contain the actual number of bucket chunks for the cache stored in the file.

Author: valyala

file.go

@@ -144,7 +144,7 @@ func load(filePath string, maxBytes int) (*Cache, error) {
 		maxBucketBytes := uint64((maxBytes + bucketsCount - 1) / bucketsCount)
 		expectedBucketChunks := (maxBucketBytes + chunkSize - 1) / chunkSize
 		if maxBucketChunks != expectedBucketChunks {
-			return nil, fmt.Errorf("cache file %s contains maxBytes=%d; want %d", filePath, maxBytes, expectedBucketChunks*chunkSize*bucketsCount)
+			return nil, fmt.Errorf("cache file %s contains unexpected number of bucket chunks; got %d; want %d", filePath, maxBucketChunks, expectedBucketChunks)
 		}
 	}