Fix for batch job CPU count if --ntasks-per-node specified

and max_nodes == min_nodes or no max_nodes specified
bug introduced in commit 1b7f5b91c18e747dd4a27fc1f64c000f04e78669
fix for bug 343
Set srun default task count properly when --ntasks-per-node specified

Similar problem to that described in bug 343 for sbatch
There are many differences in the salloc/srun/sbatch argument
processing that should probably be made more uniform, but no time
to do so now
Note nature of past two commits