Fix use of hourly msgpack file

[shorowit]

Pull Request Description

Hit this error in a BEopt test now that most of our end uses are derived from Output:Meters instead of Output:Variables as a result of #1456. One can replicate the issue by having no hourly Output:Variable requests (e.g., remove any HVAC systems) but request emissions calculations (which require hourly data).

Test file:
test.xml

Checklist

PR Author: Check these when they're done. Not all may apply. strikethrough and check any that do not apply.

PR Reviewer: Verify each has been completed.

• Schematron validator (EPvalidator.xml) has been updated
• Sample files have been added/updated (openstudio tasks.rb update_hpxmls)
• Tests have been added/updated (e.g., HPXMLtoOpenStudio/tests/test*.rb and/or workflow/tests/test*.rb)
• Documentation has been updated
• Changelog has been updated
• openstudio tasks.rb update_measures has been run
• No unexpected changes to simulation results of sample files