Fix Coverity Scan CID 300402 (Variable header going out of scope leaks the storage it points to.)

openair2/ENB_APP/CONTROL_MODULES/MAC/flexran_agent_mac.c

@@ -1214,6 +1214,10 @@ int flexran_agent_mac_create_empty_ul_config(mid_t mod_id, Protocol__FlexranMess
   return 0;
 
  error:
+  if(header){
+      free(header);
+      header = NULL;
+  }
   return -1;
 }