Select/cray - Log NHC run time on "scontrol reconfig"

Running "scontrol reconfig" releases resources for jobs waiting for
  the completion of Node Health Check so that other jobs can run.
  Cray says to always wait for NHC to complete, but in extreme
  cases that can be 2 hours, during which the entire resource
  allocation for a job may be unusable. Per advice from NERSC,
  the logic to release resources is unchanged, but logging is
  added here.