LU-15721 llite: only statfs for projid if PROJINHERIT set

LU-15721 llite: only statfs for projid if PROJINHERIT set

If projid is set on a directory but PROJINHERIT is not, do not report
the project quota for statfs.  This matches how ext4_statfs() and
xfs_fs_statfs() behave, on which Lustre project quota is modelled.

Lustre-change: https://review.whamcloud.com/47352
Lustre-commit: 4192f28733fe62173dec4a522c6589ee741df474

Fixes: e5c8f6670f ("LU-9555 quota: df should return projid-specific values")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I27cb444c3dfabc0ec693cee6fe6f9cae6db8a77a
Reviewed-on: https://review.whamcloud.com/47586
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>