UIMA operators: Be more robust if dataDirectory is not set

[markheger]

If dataDir is not set the runtime throws the following exception:
Exception in thread "Thread-14" java.lang.IllegalStateException
at com.ibm.streams.operator.internal.runtime.api.PE.getDataDirectory(PE.java:211)
at com.ibm.streamsx.nlp.AbstractUimaOperator.initialize(AbstractUimaOperator.java:506)
at com.ibm.streamsx.nlp.RutaText.initialize(RutaText.java:156)
at com.ibm.streams.operator.internal.runtime.api.OperatorAdapter.initialize(OperatorAdapter.java:736)
at com.ibm.streams.operator.internal.jni.JNIBridge.(JNIBridge.java:274)

Operator should use "/tmp" as installation root for PEAR file installation if PE.getDataDirectory() throws an exception.