Fix rpointer check in buildnml

[alperaltuntas]

Account for date stamps while checking whether rpointer files exist.

[mnlevy1981]

Have you talked to @jedwards4b about what should be expected? I think we want to continue to support the old file format (e.g. restarting from CESM2 case with rpointer.ocn and no date stamp), and we also probably want to make sure a specific restart file has been created rather than looking for anything that fits the rpointer.ocn.YYYY-MM-DD-SSSSS pattern. If CESM is trying to restart from 0001-01-07-00000 and the only ocean rpointer file is rpointer.ocn.0001-01-06-00000 then we should catch that in buildnml

[jedwards4b]

@alperaltuntas I have a fix for Mike's comment that I can push to your branch if you like?

[jedwards4b]

This works, you can also get the precise datestamp with:

   drv_ptr = case.get_value("DRV_RESTART_POINTER")                                                                                                              
      if drv_ptr:                                                                                                                                                  
          mom_ptr = drv_ptr.replace("cpl","ocn")              

[mnlevy1981]

This works, you can also get the precise datestamp with:

   drv_ptr = case.get_value("DRV_RESTART_POINTER")                                                                                                              
      if drv_ptr:                                                                                                                                                  
          mom_ptr = drv_ptr.replace("cpl","ocn")              

I like this approach, but my test case doesn't have DRV_RESTART_POINTER -- was it added in CIME or in CMEPS? And which tag?

[jedwards4b]

Still in a cmeps PR: ESCOMP/CMEPS#500

[mnlevy1981]

If DRV_RESTART_POINTER isn't available in CMEPS yet, and this PR lets users restart then I'm all for using it as a placeholder (but we should clean up the logic in the beta05 series)