Simplify calculation of overdue files list

The casting to FileTime is needless and the compareTo method is not as
clear to read as a simple great than operator.

Change-Id: Ib736a7e92324e165635c5271fe24bdc4bc977e0f

src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/ArchiveRepositoryRemover.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/ArchiveRepositoryRemover.java b/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/ArchiveRepositoryRemover.java
index 0b343c9..bb9138e 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/ArchiveRepositoryRemover.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/deleteproject/fs/ArchiveRepositoryRemover.java
@@ -32,7 +32,6 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.attribute.FileTime;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.ScheduledFuture;
@@ -113,13 +112,13 @@
   private List<Path> listOverdueFiles(long duration) {
     List<Path> files = new ArrayList<>();
     File targetDir = config.getArchiveFolder().toFile();
-    FileTime nowTime = FileTime.fromMillis(TimeMachine.now().toEpochMilli());
+    long nowTimestamp = TimeMachine.now().toEpochMilli();
 
     for (File repo : targetDir.listFiles()) {
       try {
-        FileTime lastModifiedTime = Files.getLastModifiedTime(repo.toPath());
-        FileTime expires = FileTime.fromMillis(lastModifiedTime.toMillis() + duration);
-        if (nowTime.compareTo(expires) > 0) {
+        long lastModifiedTime = Files.getLastModifiedTime(repo.toPath()).toMillis();
+        long expiryTimestamp = lastModifiedTime + duration;
+        if (nowTimestamp > expiryTimestamp) {
           files.add(repo.toPath());
         }
       } catch (IOException e) {