Merge pull request #108 from NASA-PDS/harvest_213

NASA-PDS/harvest#213: Update to fix regression to skip files if already registered

src/main/java/gov/nasa/pds/registry/common/connection/aws/SearchRespWrap.java

@@ -104,7 +104,7 @@ public Set<String> nonExistingIds(Collection<String> from_ids)
       throws UnsupportedOperationException, IOException {
     HashSet<String> results = new HashSet<String>(from_ids);
     for (Hit<Object> hit : this.parent.hits().hits()) {
-      if (from_ids.contains(hit.id())) from_ids.remove(hit.id());
+      if (from_ids.contains(hit.id())) results.remove(hit.id());
     }
     return results;
   }