btrfs: remove pointless empty log context list check when syncing log

btrfs: remove pointless empty log context list check when syncing log

When syncing the log, if we get an error when updating the log root, we
check first if the log root tree context is in a log context list, and if
so it deletes from the log root tree context from the list. This check
however is pointless because at this moment the context is always in a
list, he have just added it to a context list. The check became pointless
after commit a93e01682e28 ("btrfs: remove no longer needed use of
log_writers for the log root tree"). So remove this now pointless empty
list check.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>