[mridulpathak]

Two fixes in ProductConfigWrapper:

• ConfigItem.configItem was declared transient, although GenericValue is serializable, so once a ProductConfigWrapper had been deserialized, isSingleChoice, getQuestion, getDescription and toString failed with a NullPointerException. The field is now serialized like configItemAssoc next to it.
• ConfigOption.recalculateOptionPrice called calculateProductPrice twice with the same arguments and checked only the second result for errors. It now makes the call once, checks that result, and takes the delegator from the wrapper's getter instead of its transient field.