Using the -a flag can cause an unhandled exception

[sterlingbaldwin]

INFO       2019-03-11 15:10:07,152 Scanning /p/user_pub/work/E3SM/1_0/historical/1deg_atm_60-30km_ocean/ocean/native/model-output/mon/ens1/v1/mpaso.hist.am.timeSeriesStatsMonthly.1850-01-01.nc
INFO       2019-03-11 15:10:07,172 Aggregate dimension not found: Time
Traceback (most recent call last):
  File "/usr/local/conda/envs/esgf-pub/bin/esgpublish", line 782, in <module>
    main(sys.argv[1:])
  File "/usr/local/conda/envs/esgf-pub/bin/esgpublish", line 754, in main
    commitEvery=commitEvery, validate_standard_name=validate_standard_name)
  File "/usr/local/conda/envs/esgf-pub/lib/python2.7/site-packages/esgcet/publish/utility.py", line 857, in iterateOverDatasets
    pid_connector=pid_connector, test_publication=test_publication, commitEvery=commitEvery, **context)
  File "/usr/local/conda/envs/esgf-pub/lib/python2.7/site-packages/esgcet/publish/extract.py", line 200, in extractFromDataset
    addNewVersion, fobjs = createDataset(dset, pathlist, session, handler, cfHandler, configOptions, aggregateDimensionName=aggregateDimensionName, offline=offline, progressCallback=progressCallback, stopEvent=stopEvent, extraFields=extraFields, masterGateway=masterGateway, useVersion=useVersion, commitEvery=commitEvery, **context)
  File "/usr/local/conda/envs/esgf-pub/lib/python2.7/site-packages/esgcet/publish/extract.py", line 368, in createDataset
    extractFromFile(dset, f, file, session, handler, cfHandler, aggdimName=aggregateDimensionName, varlocate=varlocate, exclude_variables=exclude_variables, perVariable=perVariable, **context)
  File "/usr/local/conda/envs/esgf-pub/lib/python2.7/site-packages/esgcet/publish/extract.py", line 780, in extractFromFile
    filevar.aggdim_first = float(aggvarFirst)
UnboundLocalError: local variable 'aggvarFirst' referenced before assignment

The aggvarFirst variable is set inside an if block, if that block is skipped because its condition if false, the variable may be referenced later causing an referenced before assignment error.

[sterlingbaldwin]

The secondary issue here is that there is in fact a dimension named Time, and esgpublish isnt able to find it.