Update Process Data Context to retrieve proc def key from context rath… (#77)

Author: HarishMalavade

engine/src/main/java/org/finos/fluxnova/bpm/engine/impl/interceptor/ProcessDataContext.java

@@ -204,7 +204,7 @@ public boolean pushSection(ExecutionEntity execution) {
     }
 
     if (isNotBlank(mdcPropertyDefinitionKey)) {
-      addToStack(execution.getProcessDefinition().getKey(), mdcPropertyDefinitionKey);
+      addToStack(execution.getProcessDefinitionKey(), mdcPropertyDefinitionKey);
     }
 
     sections.sealCurrentSection();