Change 'usage' tres to be 'ic' and 'fs' TRES.

doc/html/tres.shtml

doc/man/man5/slurm.conf.5

src/common/assoc_mgr.c

src/common/read_config.h

src/common/slurmdb_defs.c

src/plugins/accounting_storage/mysql/as_mysql_tres.c

..._gather_filesystem/lustre/acct_gather_filesystem_lustre.c

..._gather_interconnect/ofed/acct_gather_interconnect_ofed.c

src/plugins/jobacct_gather/common/common_jag.c

src/sacct/print.c

src/slurmctld/controller.c