Revise sh:not structure in new sh:datatype test

Commit ba77dea used a design pattern that I now believe is not
applicable.  This patch revises the new shape to the corrected from now
in PR 564.

No effects were observed on Make-managed files.

References:
* #562
* 6669aab

Signed-off-by: Alex Nelson <alexander.nelson@nist.gov>

ontology/owl/owl.ttl

@@ -295,12 +295,9 @@ uco-owl:ontologyIRI-versionIRI-prerequisite-shape
 
 uco-owl:sh-datatype-objects-shape
 	a sh:NodeShape ;
-	sh:node [
+	sh:not [
 		a sh:NodeShape ;
-		sh:not [
-			a sh:NodeShape ;
-			sh:class owl:Class ;
-		] ;
+		sh:class owl:Class ;
 	] ;
 	sh:targetObjectsOf sh:datatype ;
 	.