xfs: don't fill statvfs with project quota for a directory if it was not enabled.

Check if the project quota is running or not before performing
xfs_qm_statvfs(), just return if not.  Otherwise the ASSERT
XFS_IS_QUOTA_RUNNING in xfs_qm_dqget will be popped.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

fs/xfs/xfs_super.c

@@ -1072,7 +1072,7 @@ xfs_fs_statfs(
 
 	spin_unlock(&mp->m_sb_lock);
 
-	if ((ip->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) ||
+	if ((ip->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 	    ((mp->m_qflags & (XFS_PQUOTA_ACCT|XFS_OQUOTA_ENFD))) ==
 			      (XFS_PQUOTA_ACCT|XFS_OQUOTA_ENFD))
 		xfs_qm_statvfs(ip, statp);