use constant for the SCCS directory

Author: vladak

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

@@ -43,6 +43,8 @@
  */
 final class SCCSHistoryParser {
 
+    static final String SCCS_DIR_NAME = "SCCS";
+
     boolean pass;
     boolean passRecord;
     boolean active;
@@ -258,7 +260,7 @@ private static File getSCCSFile(File file) {
 
     @Nullable
     static File getSCCSFile(String parent, String name) {
-        File f = Paths.get(parent, "SCCS", "s." + name).toFile();
+        File f = Paths.get(parent, SCCS_DIR_NAME, "s." + name).toFile();
         if (!f.exists()) {
             return null;
         }

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

@@ -166,7 +166,7 @@ boolean isRepositoryFor(File file, CommandTimeoutType cmdType) {
             if (f.isDirectory()) {
                 return true;
             }
-            return new File(file, "SCCS").isDirectory();
+            return new File(file, SCCSHistoryParser.SCCS_DIR_NAME).isDirectory();
         }
         return false;
     }