Added -FF flag to rsync invocation in synchronize

The `-FF` option causes rsync to look for files in the source directory named `.rsync-filter` and uses them to filter directories underneath them. If no `.rsync-filter` files are found, the behavior is identical to the command run without the -FF option. This flag does not sync the .rsync-filter files themselves.

This change should be backwards compatible and not produce surprising behavior for users, since they are unlikely to create `.rsync-filter` files unintentionally.

library/files/synchronize

@@ -183,7 +183,7 @@ def main():
     owner = module.params['owner']
     group = module.params['group']
 
-    cmd = '%s --delay-updates --compress --timeout=%s' % (rsync, rsync_timeout)
+    cmd = '%s --delay-updates -FF --compress --timeout=%s' % (rsync, rsync_timeout)
     if module.check_mode:
         cmd = cmd + ' --dry-run'
     if delete: