added the setJDK method.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1305 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/Project.java

@@ -158,6 +158,14 @@ public class Project extends Job<Project,Build> {
         return getParent().getJDK(jdk);
     }
 
+    /**
+     * Overwrites the JDK setting.
+     */
+    public synchronized void setJDK(JDK jdk) throws IOException {
+        this.jdk = jdk.getName();
+        save();
+    }
+
     public int getQuietPeriod() {
         return quietPeriod!=null ? quietPeriod : getParent().getQuietPeriod();
     }