Explicitly set user name of UID=0 to "root" for cleaner operation on

NEWS

src/api/job_info.c

src/common/uid.c

src/common/uid.h

src/plugins/jobcomp/filetxt/jobcomp_filetxt.c

src/slurmctld/sched_upcalls.c

src/smap/configure_functions.c

src/smap/job_functions.c

src/squeue/print.c

src/squeue/sort.c