dquot: move dquot drop responsibility into the filesystem

Currently clear_inode calls vfs_dq_drop directly.  This means
we tie the quota code into the VFS.  Get rid of that and make the
filesystem responsible for the drop inside the ->clear_inode
superblock operation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index cb7f67d..13eb5d4 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1087,6 +1087,8 @@
 	mlog_bug_on_msg(OCFS2_SB(inode->i_sb) == NULL,
 			"Inode=%lu\n", inode->i_ino);
 
+	vfs_dq_drop(inode);
+
 	/* To preven remote deletes we hold open lock before, now it
 	 * is time to unlock PR and EX open locks. */
 	ocfs2_open_unlock(inode);