fixes to test_dsync/test_xattr.sh and test_dsync/test_xattr.py

[ofaaland]

Fixes two issues:

1. The command line generated in test_xattr.py to execute test_xattr.sh and run the test was wrong. Fix that.
2. The output of "xattr -l" needs to be sorted for the xattr comparison to work consistently

Tested on lustre and xfs

[carbonneau1]

We no longer copy extended attributes by default, right?

[ofaaland]

Updated to change the commit messages to clarify this affects a test under test_dsync/

[ofaaland]

We no longer copy extended attributes by default, right?

Based on the manpage dsync.1 discussion of --xattr and the commit message for adding that option, 96a9fe7, we used to copy all xattrs, and now the default is to copy non-lustre xattrs.

This test doesn't actually check what dsync does if --xattr is not provided, so I'm not sure. I'll look.

[ofaaland]

Altered the test so it tests dsync without --xattr as well as with --xattr {none,all,non-lustre}

[ofaaland]

We no longer copy extended attributes by default, right?

Based on the manpage dsync.1 discussion of --xattr and the commit message for adding that option, 96a9fe7, we used to copy all xattrs, and now the default is to copy non-lustre xattrs.

This test doesn't actually check what dsync does if --xattr is not provided, so I'm not sure. I'll look.

@carbonneau1 I checked, and dsync copies non-lustre xattrs by default. I modified the test to check that functionality. Please review the additional change, thanks.