Tracebake if deleting a glob

A possibly misguided attempt to try a glob syntax causes a traceback:

[zaitcev@suzdal tests]$ PYTHONPATH=/q/zaitcev/hail/python-swiftclient-tip /q/zaitcev/hail/python-swiftclient-tip/bin/swift -V 3 -A https://rhev-a24c-01.os.lab.eng.bos.redhat.com:35357/v3 -U ksuserten:ksuser -K *** delete shardcont1 '16*'
Traceback (most recent call last):
  File "/q/zaitcev/hail/python-swiftclient-tip/bin/swift", line 24, in <module>
    sys.exit(main())
  File "/q/zaitcev/hail/python-swiftclient-tip/swiftclient/shell.py", line 1971, in main
    globals()['st_%s' % args[0]](parser, argv[1:], output)
  File "/q/zaitcev/hail/python-swiftclient-tip/swiftclient/shell.py", line 173, in st_delete
    if r.get('attempts') > 1 else '')
TypeError: '>' not supported between instances of 'NoneType' and 'int'
[zaitcev@suzdal tests]$

This happens on trunk, release tag 3.8.1.

If globbing is not supported, we ought to report a better error. Something like "not supported" would work. But I'll take "16* is not found", too.