JCR-2323: Wrong Upload size on cluster mode

Problem analysis:
- On clustering mode : for files whose size exceeds the buffer value (by default 200K), the steps are as follows:
	- The property jcr:data is built in the first node having the value of an object (more precisely of StremValuePropertyData type) that has an instance variable with the name "file" containing the file path in the value storage and point on a path in the swap file.
	- When this property is applied to the second node and the object is intercepted, the logic responsible for the serialization of the object simply checks if the file exists in the system or not (which is not the case) and make it "null" if necessary.

Fix description
- When the  path file of StremValuePropertyData is null, do forceLoad the property data from the DB storage.