Put allocator block references on forced unmount

During forced unmount commits abort due to errors and the open
transaction is left in a dirty state that is cleaned up by
scoutfs_shutdown_trans().   It cleans all the dirty blocks in the commit
write context with scoutfs_block_writer_forget_all(), but it forgot to
call scoutfs_alloc_prepare_commit() to put the block references held by
the allocator.

This was generating leaked block warnings during testing that used
forced unmount.  It wouldn't affect regular operations.

Signed-off-by: Zach Brown <zab@versity.com>

kmod/src/trans.c

@@ -640,6 +640,7 @@ void scoutfs_shutdown_trans(struct super_block *sb)
 			tri->write_workq = NULL;
 		}
 
+		scoutfs_alloc_prepare_commit(sb, &tri->alloc, &tri->wri);
 		scoutfs_block_writer_forget_all(sb, &tri->wri);
 
 		kfree(tri);