Correctly initialize protocol_ctxt in F1 code
In the previous version, not all fields, and in particular the eNB_index, were not initialized, leading to errors when they were used (e.g., the PDCP code checks that eNB_index == 0).
In the previous version, not all fields, and in particular the eNB_index, were not initialized, leading to errors when they were used (e.g., the PDCP code checks that eNB_index == 0).