Fix linter issues: unconvert

Makefile

@@ -123,6 +123,7 @@ gometalinter: require-gometalinter
 	    --enable=maligned \
 	    --enable=misspell \
 	    --enable=nakedret \
+	    --enable=unconvert \
 	    --enable=unparam \
 	    --enable=vet \
 	    --exclude "^internal/.*\.pb\.go" \

boltdb/attrstore.go

@@ -262,8 +262,8 @@ func (s *attrStore) BlockData(i uint64) (map[uint64]map[string]interface{}, erro
 	defer tx.Rollback()
 
 	// Move to the start of the block.
-	min := u64tob(uint64(i) * attrBlockSize)
-	max := u64tob(uint64(i+1) * attrBlockSize)
+	min := u64tob(i * attrBlockSize)
+	max := u64tob((i + 1) * attrBlockSize)
 	cur := tx.Bucket([]byte("attrs")).Cursor()
 	for k, v := cur.Seek(min); k != nil; k, v = cur.Next() {
 		// Exit if we're past the end of the block.

cache.go

@@ -114,7 +114,7 @@ func (c *lruCache) Top() []bitmapPair {
 	for id, n := range c.counts {
 		a = append(a, bitmapPair{
 			ID:    id,
-			Count: uint64(n),
+			Count: n,
 		})
 	}
 	sort.Sort(bitmapPairs(a))

field.go

@@ -1072,9 +1072,9 @@ func (f *Field) importValue(columnIDs []uint64, values []int64) error {
 	dataByFragment := make(map[importKey]importValueData)
 	for i := range columnIDs {
 		columnID, value := columnIDs[i], values[i]
-		if int64(value) > bsig.Max {
+		if value > bsig.Max {
 			return fmt.Errorf("%v, columnID=%v, value=%v", ErrBSIGroupValueTooHigh, columnID, value)
-		} else if int64(value) < bsig.Min {
+		} else if value < bsig.Min {
 			return fmt.Errorf("%v, columnID=%v, value=%v", ErrBSIGroupValueTooLow, columnID, value)
 		}
 

server/server.go

@@ -230,7 +230,7 @@ func (m *Command) SetupServer() error {
 
 	diagnosticsInterval := time.Duration(0)
 	if m.Config.Metric.Diagnostics {
-		diagnosticsInterval = time.Duration(defaultDiagnosticsInterval)
+		diagnosticsInterval = defaultDiagnosticsInterval
 	}
 
 	statsClient, err := newStatsClient(m.Config.Metric.Service, m.Config.Metric.Host)

translate.go

@@ -862,7 +862,7 @@ func (idx *index) lookupKey(offset int64) []byte {
 func (idx *index) alloc(capacity uint64) {
 	idx.elems = make([]elem, capacity)
 	idx.threshold = (capacity * uint64(idx.loadFactor)) / 100
-	idx.mask = uint64(capacity - 1)
+	idx.mask = capacity - 1
 }
 
 func (idx *index) dist(hash, i uint64) uint64 {