build: Enable gometalinter "unconvert" check

lib/scanner/blocks.go

@@ -56,7 +56,7 @@ func Blocks(r io.Reader, blocksize int, sizehint int64, counter Counter) ([]prot
 		}
 
 		if counter != nil {
-			counter.Update(int64(n))
+			counter.Update(n)
 		}
 
 		// Carve out a hash-sized chunk of "hashes" to store the hash for this
@@ -72,7 +72,7 @@ func Blocks(r io.Reader, blocksize int, sizehint int64, counter Counter) ([]prot
 		}
 
 		blocks = append(blocks, b)
-		offset += int64(n)
+		offset += n
 
 		hf.Reset()
 		whf.Reset()

lib/scanner/walk.go

@@ -163,7 +163,7 @@ func (w *walker) walk() (chan protocol.FileInfo, error) {
 
 		for file := range toHashChan {
 			filesToHash = append(filesToHash, file)
-			total += int64(file.Size)
+			total += file.Size
 		}
 
 		realToHashChan := make(chan protocol.FileInfo)