Merge pull request #738 from fluidnotions/activiti6

bug fix for null overwrite of formKey if it exissts

modules/activiti-ui/activiti-app-logic/src/main/java/com/activiti/service/runtime/DeploymentServiceImpl.java

@@ -333,7 +333,7 @@ public class DeploymentServiceImpl implements DeploymentService {
             }
         }
         
-        if (StringUtils.isEmpty(formKey)) {
+        if (StringUtils.isEmpty(finalFormKey)) {
             finalFormKey = formKey;
         }