stop relying on remote job id

[bernstei]

It's sometimes nice to resubmit a remote job by hand (e.g. after tweaking up the max runtime). However, right now expyre will be confused if it tries to check on the new job while it's running, because the jobid won't match what's saved in the database. After the job is done it's fine, because the jobid doesn't matter. Maybe expyre should not even save the jobid, and just extract it as needed (e.g. for qdel) by filtering the output of qstat based on the job name, which is already a unique string. Note that the job name can be mangled by the queuing system wrappers, to avoid forbidden characters, so you can't just use the hash part of the rundir - you have to mangle it the same way.