CRM-13474 : fix for warning displayed - undefined index 'street_address'

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* CRM-13474: Undefined index: street_address in CRM_Import_Parser_Contact->createContact()
  http://issues.civicrm.org/jira/browse/CRM-13474
Merge pull request #1722 from pratik-joshi/CRM-13474

CRM-13474 : fix for warning displayed - undefined index 'street_address'