vfs: remove dget() from dentry_unhash()

This serves no useful purpose that I can discern.  All callers (rename,
rmdir) hold their own reference to the dentry.

A quick audit of all file systems showed no relevant checks on the value
of d_count in vfs_rmdir/vfs_rename_dir paths.

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/hpfs/namei.c

@@ -414,7 +414,6 @@ again:
 		mutex_unlock(&hpfs_i(inode)->i_parent_mutex);
 		dentry_unhash(dentry);
 		if (!d_unhashed(dentry)) {
-			dput(dentry);
 			hpfs_unlock(dir->i_sb);
 			return -ENOSPC;
 		}
@@ -422,7 +421,6 @@ again:
 		    !S_ISREG(inode->i_mode) ||
 		    get_write_access(inode)) {
 			d_rehash(dentry);
-			dput(dentry);
 		} else {
 			struct iattr newattrs;
 			/*printk("HPFS: truncating file before delete.\n");*/
@@ -430,7 +428,6 @@ again:
 			newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
 			err = notify_change(dentry, &newattrs);
 			put_write_access(inode);
-			dput(dentry);
 			if (!err)
 				goto again;
 		}