xfs/106: rewrite to make it a reliable regression test

xfs/106: rewrite to make it a reliable regression test

xfs/106 is testing basic functions of xfs_quota command, but
there're three problems prevent people from running it as a reliable
regression test (i.e. it's not in 'auto' group):

- It tests unavailable commands in current xfs_quota, e.g. "warn"
- Lack of test coverage of important commands, e.g. "disable,
  enable, off and remove" commands
- Test output doesn't match golden image

So rewrite this case to test as many xfs_quota sub-commands and
options as possible and add it to 'auto' group, except:

- some "-v" options
- all "-a" options, because it's hard to get deterministic output
- default quota, this should be already covered by other tests
- project command options, I will write another case to test it
- report command -l option, which is a new option and will cause
  failure when testing with xfsprogs prior to 3.1 version.
- quot command -c option, which may output different histogram in
  different systems or hosts.
- warn command, which is not currently implemented.
- print, df, free, help, quit and path commands.

Signed-off-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>