Fixes the import of the deadline for planner files

FEA: ItEr77S05BasicProjectImport

libreplan-webapp/src/main/java/org/libreplan/importers/MPXJProjectFileConversor.java

@@ -94,6 +94,10 @@ public class MPXJProjectFileConversor {
 
         importData.milestones = getImportMilestones(file.getChildTasks());
 
+        // MPXJ don't provide a deadline for the project so we take the finish
+        // date
+        importData.deadline = header.getFinishDate();
+
         return importData;
 
     }