ocfs2: Let inode be really deleted when ocfs2_mknod_locked() fails

We forgot to set i_nlink to 0 when returning due to error from ocfs2_mknod_locked()
and thus inode was not properly released via ocfs2_delete_inode() (e.g. claimed
space was not released). Fix it.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>