[jvstm-common] Remove synchronized from reload() in VBox

It is not strictly necessary.  It only existed to prevent two reload requests
regarding the same vbox to hit the repository.  However, the actual required
synchronization is performed in the mergeVersions method.

Now that VBox is used also in the lock-free implementation, the extraneous
synchronized was removed so that it does not prevent the lock-free behavior.
Milestone: Multiple fixes. Implement reload. Missing handling of RemoteCommitOnlyTransaction

  * Initial implementation of the lock-free reload mechanism. For now, there
    is no optimization using the LAST_CONSOLIDATED_VALUE.

  * Refactor the initialization procedure to make it friendlier to jvstm-lf

  * Use NOT_LOADED_BODY constant consistently across the code.

  * Fix: Initialization of JVSTM in secondary nodes now correctly sets the
    last committed version.  We make a non-conflicting commit request to get
    to a known state.
[jvstm-lf/infinispan] Optimize puts by ignoring return values

This is especially relevant in distributed mode where we can avoid unnecessary
remote lookups.
Handle remote commit requests