Add missing `return` statement

Change-Id: Ide75519272c0bd636d3476a9a413edcfc6212cf9

src/main/java/com/googlesource/gerrit/plugins/healthcheck/check/ChangesIndexHealthCheck.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/healthcheck/check/ChangesIndexHealthCheck.java b/src/main/java/com/googlesource/gerrit/plugins/healthcheck/check/ChangesIndexHealthCheck.java
index fada9aa..3267469 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/healthcheck/check/ChangesIndexHealthCheck.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/healthcheck/check/ChangesIndexHealthCheck.java
@@ -107,7 +107,7 @@
 
   private Optional<ChangesIndexLockFiles> getChangesIndexLockFiles(Path indexDir) {
     if (!isLuceneIndex) {
-      Optional.empty();
+      return Optional.empty();
     }
 
     FileBasedConfig cfg =