ocfs2/dlm: clean up useless BUG_ON default case in dlm_finalize_reco_handler()

The value of 'stage' must be between 1 and 2, so the switch can't reach
the default case.

Link: http://lkml.kernel.org/r/57FB5EB2.7050002@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>