Reindexing when no metrics is available

[spacemansteve]

The nonbib/data pipeline always send both nonbib and metrics. For zndo-related bibcodes from asclepias, we do not have metrics data. This lack of metrics data is generates an exception during the metrics phase of the index task.

Task=1194b781-e361-40c7-aed9-3b6f968223de failed.
args=[[u'2017zndo....292632C', u'2018zndo...1146705C', u'2018zndo...1230529C']]
kwargs={u'update_solr': True, u'update_metrics': True, u'force': True, u'update_links': True, u'ignore_checksums': True}
trace=Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/celery/app/trace.py", line 375, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/celery/app/trace.py", line 632, in __protected_call__
    return self.run(*args, **kwargs)
  File "/app/adsmp/tasks.py", line 177, in task_index_records
    m['bibcode'] = bibcode
TypeError: 'NoneType' object does not support item assignment```