Added missing deallocation in RLC UM in case of too small pdu

lib/src/upper/rlc_um.cc

@@ -279,6 +279,7 @@ int  rlc_um::build_data_pdu(uint8_t *payload, uint32_t nof_bytes)
 
   if(pdu_space <= head_len + 1)
   {
+    pool->deallocate(pdu);
     log->warning("%s Cannot build a PDU - %d bytes available, %d bytes required for header\n",
                  rrc->get_rb_name(lcid).c_str(), nof_bytes, head_len);
     return 0;