Fix JDK 1.8 compilation problem

Author: rodrigc

Diff for: src/main/java/com/cloudbees/plugins/flow/FlowRun.java

@@ -134,7 +134,7 @@ public BuildFlow getBuildFlow() {
     }
 
     public void doGetDot(StaplerRequest req, StaplerResponse rsp) throws IOException {
-        new DOTExporter().export(rsp.getWriter(), jobsGraph);
+        new DOTExporter<JobInvocation, JobEdge>().export(rsp.getWriter(), jobsGraph);
     }
 
     public synchronized void addBuild(JobInvocation job) throws ExecutionException, InterruptedException {

Diff for: src/test/java/com/cloudbees/plugin/flow/TestDSLExtension.java

@@ -38,7 +38,7 @@
 public class TestDSLExtension extends BuildFlowDSLExtension {
     @Override
     public Object createExtension(String extensionName, FlowDelegate dsl) {
-        Map m = new TreeMap();
+        Map<String, Object> m = new TreeMap<String, Object>();
         m.put("dsl",dsl);
         m.put("name",extensionName);
         return m;