las binaries are not killed when merge starts
Imported issue: Initially reported by @zimmerma in https://gforge.inria.fr/tracker/?group_id=2065&aid=21718
with revision 2cabed38, it appears some las jobs are still running when merge starts. This can be reproduced with the following 90-digit factorization by looking at top
when merge starts:
$ ./cado-nfs.py 482940676938975075806475467716373950242726509723517010302524110187257004202892794033435637