Problems with missing forecast hours

[Brian-Jamison]

Deployment of HRRR-CAR revealed that having a missing forecast hour causes an index slicing error, and the job fails and restarts until the deadline time set in the rocoto xml.

We need to add an exception to "ignore" this hour for most plots, and either stop any processing of run-total plots at that hour, or add some text to the plots noting any missing hours.