jbd2: remove pointless assertion in __journal_remove_journal_head

Only when jh->b_jcount = 0 in jbd2_journal_put_journal_head, we are allowed
to call __journal_remove_journal_head. This assertion is meaningless,
just remove it.

Signed-off-by: Shijie Luo <luoshijie1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200123070054.50585-1-luoshijie1@huawei.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>