Fixed issue with misnamed property.

Although `modification` was the official name of one of the dates associated to TestAction objects,
both examples and OEB_level2_data_migration have been using `reception` instead. So, to keep entries
and 1.0 model coherent, the property has been renamed.

Author: jmfernandez

json-schemas/1.0.x/testAction.json

@@ -132,7 +132,7 @@
 					"type": "string",
 					"format": "date-time"
 				},
-				"modification": {
+				"reception": {
 					"title": "Last modification date of the test action",
 					"type": "string",
 					"format": "date-time"
@@ -143,6 +143,7 @@
 					"format": "date-time"
 				}
 			},
+			"additionalProperties": false,
 			"required": ["creation"]
 		},
 		"metadata": {