ItEr41S16ImplantacionAplicacionItEr40S21: [Bug #218] Fixing bug.

The error is caused because a calendar capacity is null at database. It could be solved by a migration, but checking it in code too.

navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/ResourceCalendar.java

@@ -37,6 +37,9 @@ public class ResourceCalendar extends BaseCalendar {
     private Integer capacity = 1;
 
     public Integer getCapacity() {
+        if (capacity == null) {
+            return 1;
+        }
         return capacity;
     }