CRM-13026 : exclude test jobs

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* CRM-13026: Advanced Search : Display results as Mailings
  http://issues.civicrm.org/jira/browse/CRM-13026
* CRM-13026-exclude-test-jobs:
  http://issues.civicrm.org/jira/browse/CRM-13026-exclude-test-jobs
Merge pull request #1622 from pratik-joshi/CRM-13026-exclude-test-jobs

CRM-13026 : exclude test mailing jobs from searching