PROV-1025 Don't throw an error if there is no setting for current_location_criteria

 Invalid argument supplied for foreach()

 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/models/ca_objects.php:1736
 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/models/ca_objects.php:1675
 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/plugins/relationshipGenerator/relationshipGeneratorPlugin.php:196
 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/plugins/relationshipGenerator/relationshipGeneratorPlugin.php:133
 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/lib/ca/ApplicationPluginManager.php:70
 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/lib/ca/BundlableLabelableBaseModelWithAttributes.php:245
 /home/kehan/workspace/GR355-WAM-CMIS/providence/app/lib/ca/BundlableLabelableBaseModelWithAttributes.php:245
 /home/kehan/workspace/GR355-WAM-CMIS/providence/tests/plugins/relationshipGenerator/RelationshipGeneratorPluginIntegrationTest.php:280
 /home/kehan/workspace/GR355-WAM-CMIS/providence/tests/plugins/relationshipGenerator/RelationshipGeneratorPluginIntegrationTest.php:238
Merge pull request #141 from kehh/PROV-1025-FixFailingTests

PROV-1025 Don't throw an error if there is no setting for current_location_criteria