Fix forced use of oboInOwl namespace when translating OBO IDs.

This commit rewrites part of the OWLAPIObo2Owl#oboIdToIRI_load() method
so that the oboInOwlDefault parameter is only used when translating
unprefixed IDs (where it instructs to create an IRI in the oboInOwl
namespace instead of the ontology's default namespace). When translating
a prefixed ID, the IRI to construct should always use the URL prefix
dictated by the prefix.

closes #1112

oboformat/src/main/java/org/obolibrary/obo2owl/OWLAPIObo2Owl.java

@@ -1548,15 +1548,7 @@ public IRI loadOboToIRI(String id, boolean oboInOwlDefault) {
                 }
             }
         }
-        // TODO - treat_xrefs_as_equivalent
-        // special case rule for relation xrefs:
-        // 5.9.3. Special Rules for Relations
-        if (!id.contains(":")) {
-            String xid = translateShorthandIdToExpandedId(id);
-            if (!xid.equals(id)) {
-                return oboIdToIRI(xid);
-            }
-        }
+
         String[] idParts = id.split(":", 2);
         String uriPrefix;
         String localId;