Remove disable_root_jobs variable from slurm_ctl_conf_t

contribs/perlapi/libslurm/perl/conf.c

slurm/slurm.h.in

src/api/config_info.c

src/common/read_config.c

src/common/read_config.h

src/common/slurm_protocol_pack.c

src/slurmctld/partition_mgr.c

src/slurmctld/proc_req.c

src/slurmctld/read_config.c