LU-4028 quota: improve lfs quota output

- print the total allocated block/inode limit for all OSTs/MDTs
  when the verbose option is specified;
- add 'h' option to print used space in human readable format;

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: Idc9cd3d92a50744885f65e82c9ce53b332c1959a
Reviewed-on: http://review.whamcloud.com/8152
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Johann Lombardi <johann.lombardi@intel.com>