BibSched: parse_runtime_limit() tests fix

* Fixes bug in parse_runtime_limit tests which would give a limit
  range in the past, when expected returned ranges should always
  either contain the current time or being in the future.
  (closes #1432)

Tested-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Merge branch 'maint-1.1'

* maint-1.1:
  BibSched: parse_runtime_limit() tests fix