rc1: update --size-limit to 100M for flux-restore

Problem: The size limit on the flux-restore command used in rc1 is
written in bytes, which makes it difficult to determine at first glance
the value being used.

The flux-restore --size-limit option now takes suffixed arguments, so
switch to "100M" instead of 100M in bytes.

Author: grondo

etc/rc1

@@ -47,7 +47,7 @@ if test $RANK -eq 0; then
             flux module load ${backingmod} truncate
         fi
         echo "restoring content from ${dumpfile}"
-        flux restore --quiet --checkpoint --size-limit=104857600 ${dumpfile}
+        flux restore --quiet --checkpoint --size-limit=100M ${dumpfile}
         if test -n "${dumplink}"; then
             rm -f ${dumplink}
         fi