lightnvm: pblk: guarantee emeta on line close

If a line is recovered from open chunks, the memory structures for
emeta have not necessarily been properly set on line initialization.
When closing a line, make sure that emeta is consistent so that the line
can be recovered on the fast path on next reboot.

Also, remove a couple of empty lines at the end of the function.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>