augment help

Author: Vladimir Kotal

opengrok-indexer/src/main/java/org/opengrok/indexer/index/Indexer.java

@@ -516,7 +516,8 @@ public static String[] parseOptions(String[] argv) throws ParseException {
                 canonicalRoots.add(root);
             });
 
-            parser.on("--checkIndex", "Check index.").execute(v -> checkIndex = true);
+            parser.on("--checkIndex", "Check index, exit with 0 on success,",
+                    "with 1 on failure.").execute(v -> checkIndex = true);
 
             parser.on("-d", "--dataRoot", "=/path/to/data/root",
                 "The directory where OpenGrok stores the generated data.").