Fix some pointer inconsistencies in code

cmd/common.go

@@ -167,7 +167,7 @@ func Main (argStateDir string, processCallback ctwatch.ProcessCallback) {
 			ParallelFetch: *parallelFetch,
 			Quiet:         !*verbose,
 		}
-		scanner := ctwatch.NewScanner(logUri, logKey, opts)
+		scanner := ctwatch.NewScanner(logUri, logKey, &opts)
 
 		latestSTH, err := scanner.GetSTH()
 		if err != nil {

scanner.go

@@ -287,11 +287,11 @@ func (s *Scanner) Scan(startIndex int64, endIndex int64, processCert ProcessCall
 
 // Creates a new Scanner instance using |client| to talk to the log, and taking
 // configuration options from |opts|.
-func NewScanner(logUri string, publicKey crypto.PublicKey, opts ScannerOptions) *Scanner {
+func NewScanner(logUri string, publicKey crypto.PublicKey, opts *ScannerOptions) *Scanner {
 	var scanner Scanner
 	scanner.LogUri = logUri
 	scanner.publicKey = publicKey
 	scanner.logClient = client.New(logUri)
-	scanner.opts = opts
+	scanner.opts = *opts
 	return &scanner
 }