Resolve "Fix default parameters for the periodic bubble example"

Closes #25 (closed)

hysop/core/graph/graph_builder.py

@@ -564,9 +564,6 @@ class GraphBuilder(object):
         operators     = reduced_graph.vertex_properties['operators']
         nodes = [ operators[reduced_graph.vertex(vid)] for vid in self.sorted_nodes ]
         return nodes
-        import sys
-        sys.exit(1)
-
         
     def build_subgraph(self, node, current_level, **kwds):
         node_ops = []