client: Remove -u flag from server calls
client: Remove -u flag from server calls

- Don't pass "-u $userid" to server programs, since it's always optional
(now) and is implicitly passed by isr_srun().  (isr_srun() connects to the
Unix account on the server corresponding to the userid passed on the
client's command line.)

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr