createGrid takes type

src/main/java/gov/usgs/earthquake/nshmp/model/GridRuptureSet.java

@@ -65,6 +65,7 @@ class GridRuptureSet implements RuptureSet {
   private GridSourceSet createSourceSet(double weight) {
     SourceConfig.Grid config = data.sourceConfig().asGrid();
     GridSourceSet grid = GridLoader.createGrid(
+        SourceType.GRID,
         config,
         feature.source,
         locations,

src/main/java/gov/usgs/earthquake/nshmp/model/SlabRuptureSet.java

@@ -46,6 +46,7 @@ class SlabRuptureSet implements RuptureSet {
   private SlabSourceSet createSourceSet(double weight) {
     SourceConfig.Grid config = data.sourceConfig().asGrid();
     GridSourceSet delegate = GridLoader.createGrid(
+        SourceType.INTRASLAB,
         config,
         feature.source,
         locations,

src/main/java/gov/usgs/earthquake/nshmp/model/ZoneRuptureSet.java

@@ -63,6 +63,7 @@ class ZoneRuptureSet implements RuptureSet {
     SourceConfig.Grid config = data.sourceConfig().asGrid();
 
     GridSourceSet grid = GridLoader.createGrid(
+        SourceType.ZONE,
         config,
         feature.source,
         locations,