minor fix in documentation

SOL005/VNFSnapshotPackageManagement-API/IndividualVNFSnapshotPackageArtifact.robot

@@ -77,15 +77,16 @@ GET Individual VNF Snapshot Package Artifact - Conflict
     ...    Post-Conditions: none
     GET Individual VNF Snapshot Package Artifact - Not Available
     Check HTTP Response Status Code Is    409
+    Check HTTP Response Body Json Schema Is   ProblemDetails
 
 GET Individual VNF Snapshot Package Artifact - External Artifact
     [Documentation]    Test ID: 5.3.6.10.7
     ...    Test title: GET Information about an individual VNF Snapshot Package - External Artifact
-    ...    Test objective: The objective is to test that an error is returned when the "state" of the VNF snapshot package has a value different from "AVAILABLE".
+    ...    Test objective: The objective is to test that correct response code is returned the referred "Individual VNF Snapshot package artifact" is external to the main VNF snapshot package file created from a build process.
     ...    Pre-conditions: none
     ...    Reference: Clause 11.4.10.3.2 - ETSI GS NFV-SOL 005 [3] v3.3.1
     ...    Config ID: Config_prod_NFVO
-    ...    Applicability: The "state" of the VNF snapshot package has a value different from "AVAILABLE".
+    ...    Applicability: The "Individual VNF Snapshot package artifact" is external to the main VNF snapshot package file created from a build process.
     ...    Post-Conditions: none
     GET Individual VNF Snapshot Package Artifact - External
     Check HTTP Response Status Code Is    302