don't apply umask on unknown perms (Win)

Author: hboutemy

src/main/java/org/codehaus/plexus/archiver/AbstractArchiver.java

@@ -450,7 +450,7 @@ protected ArchiveEntry asArchiveEntry( @Nonnull final PlexusIoResource resource,
             throw new ArchiverException( resource.getName() + " not found." );
         }
 
-        if ( umask > 0 )
+        if ( umask > 0 && permissions != PlexusIoResourceAttributes.UNKNOWN_OCTAL_MODE )
         {
             permissions &= ~umask;
         }