Suppress output files if writing interval is zero

[arango]

Added coded to suppress creating and writing output NetCDF files, if any of the interval parameters is set to zero or greater than ntimes(ng) in input script ocean.in.

   LdefAVG(ng)=.FALSE.  if nAVG(ng) = 0  or  nAVG(ng) > ntimes(ng)
   LdefDIA(ng)=.FALSE.  if nDIA(ng) = 0  or  nDIA(ng) > ntimes(ng)
   LdefFLT(ng)=.FALSE.  if nFLT(ng) = 0  or  nFLT(ng) > ntimes(ng)
   LdefHIS(ng)=.FALSE.  if nHIS(ng) = 0  or  nHIS(ng) > ntimes(ng)
   LdefRST(ng)=.FALSE.  if nRST(ng) = 0  or  nRST(ng) > ntimes(ng)
   LdefSTA(ng)=.FALSE.  if nSTA(ng) = 0  or  nSTA(ng) > ntimes(ng)

Many thanks to Mark Hadfield for bringing this to my attention.