only set partition property if we're writing

Author: mneedham

algo/src/main/java/org/neo4j/graphalgo/LabelPropagationProc.java

@@ -89,7 +89,6 @@ public Stream<LabelPropagationStats> labelPropagation(
 
         LabelPropagationStats.Builder stats = new LabelPropagationStats.Builder()
                 .iterations(iterations)
-                .partitionProperty(partitionProperty)
                 .weightProperty(weightProperty);
 
         GraphLoader graphLoader = graphLoader(configuration, partitionProperty, weightProperty, createPropertyMappings(partitionProperty, weightProperty));
@@ -111,6 +110,7 @@ public Stream<LabelPropagationStats> labelPropagation(
         final int[] labels = compute(direction, iterations, batchSize, concurrency, graph, stats);
         if (configuration.isWriteFlag(DEFAULT_WRITE) && partitionProperty != null) {
             stats.withWrite(true);
+            stats.partitionProperty(partitionProperty);
             write(concurrency, partitionProperty, graph, labels, stats);
         }