chained append()

Author: Vladimir Kotal

opengrok-indexer/src/main/java/org/opengrok/indexer/history/MercurialRepository.java

@@ -192,7 +192,7 @@ Executor getHistoryLogExecutor(File file, String sinceRevision, String tillRevis
                 } else {
                     // If this is non-default branch we would like to get the changesets
                     // on that branch and also follow any changesets from the parent branch.
-                    stringBuilder.append("'" + getBranch() + "'");
+                    stringBuilder.append("'").append(getBranch()).append("'");
                 }
                 if (!revisionsOnly) {
                     stringBuilder.append(")");