HO Preparation: calloc pdcp_config in DRB to Modify Item decoding

The malloced struct is initialized to garbage and when
the IE is absent, the output "PDCP reestablishment"
member (allocated in the stack) is set to a random value.

openair2/E1AP/lib/e1ap_bearer_context_management.c

@@ -1658,7 +1658,7 @@ static bool e1_decode_pdu_session_to_mod_item(pdu_session_to_mod_t *out, const E
     drb->id = drb2Mod->dRB_ID;
     // PDCP Config (O)
     if (drb2Mod->pDCP_Configuration) {
-      drb->pdcp_config = malloc_or_fail(sizeof(*drb->pdcp_config));
+      drb->pdcp_config = calloc_or_fail(1, sizeof(*drb->pdcp_config));
       CHECK_E1AP_DEC(e1_decode_pdcp_config(drb->pdcp_config, drb2Mod->pDCP_Configuration));
     }
     // SDAP Config (O)