Add one second tolerance for ZIP entries when compared in tests

When ZIP file is created the last modified time is stored in MS-DOS
formated date(if it's in the valid range for MS-DOS time), but when it's
read the last modification time from extra field data is used.

When ZIP file is created from the content of other ZIP file created with
third-party tool the last modified time might differ with one second.

Modify ArchiveFileComparator so two ZIP files are still considered equal
if their entries' last modified time vary only by one second.

Author: plamentotev

src/test/java/org/codehaus/plexus/archiver/zip/ArchiveFileComparator.java

@@ -98,7 +98,8 @@ private static void assertEquals( ZipFile file1, ZipArchiveEntry entry1,
             throws Exception
     {
         Assert.assertEquals( entry1.isDirectory(), entry2.isDirectory() );
-        Assert.assertEquals( entry1.getLastModifiedDate().getTime(), entry2.getLastModifiedDate().getTime() );
+        long timeDelta = entry1.getLastModifiedDate().getTime() - entry2.getLastModifiedDate().getTime();
+        Assert.assertTrue( Math.abs( timeDelta ) <= 1000 );
 
         final InputStream is1 = file1.getInputStream( entry1 );
         final InputStream is2 = file2.getInputStream( entry2 );