Change: Tighten reference to runlog

Using sys.host to identify the correct runlog is error prone as sys.host
is ambiguous and may be either the short or long hostname. The runlog
file is always named for the shorthostname so we should use sys.uqhost
when referencing it or it may grow without bound.
Merge pull request #347 from nickanderson/_redmine/6563

Change: Tighten reference to runlog