Generating a JSON plan with Client leads to NPE

Calling ```./bin/stratosphere info ... -p``` with a new JAPI program leads to the following exception:

```java
Exception in thread "main" java.lang.NullPointerException
at eu.stratosphere.compiler.plandump.PlanJSONDumpGenerator.dumpOptimizerPlanAsJSON(PlanJSONDumpGenerator.java:99)
at eu.stratosphere.compiler.plandump.PlanJSONDumpGenerator.getOptimizerPlanAsJSON(PlanJSONDumpGenerator.java:93)
at eu.stratosphere.client.program.Client.getOptimizedPlanAsJson(Client.java:112)
at eu.stratosphere.client.CliFrontend.info(CliFrontend.java:492)
at eu.stratosphere.client.CliFrontend.parseParameters(CliFrontend.java:856)
at eu.stratosphere.client.CliFrontend.main(CliFrontend.java:878)
```

---------------- Imported from GitHub ----------------
Url: https://github.com/stratosphere/stratosphere/issues/878
Created by: twalthr
Labels:
Created at: Tue May 27 17:27:56 CEST 2014
State: closed