LU-2361 quota: allow upgraded fs to start w/o spc accounting

LU-2361 quota: allow upgraded fs to start w/o spc accounting

All filesystems upgraded to 2.4 should run tunefs.lustre --quota to
have functional space accounting. If not done, we still allow the
filesystem to be started, but print an error on the console if the
administrator tries to enable quota.

Signed-off-by: Johann Lombardi <johann.lombardi@intel.com>
Change-Id: I98ff2cf5e5c381353b219679b935bc0584b033cc
Reviewed-on: http://review.whamcloud.com/4642
Tested-by: Hudson
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>