hotfix: put back "system" for UE to setup its IP settings

We'll need to to do it in a separate thread/process.
To be done. In the meantime, put it back. It impacts
oaisim.

openair3/NAS/UE/ESM/esm_ebr_context.c

@@ -286,7 +286,7 @@ int esm_ebr_context_create(
              LOG_TRACE(INFO, "ESM-PROC  - executing %s ",
                        command_line);
 
-             //if (system(command_line)) ; /* TODO: what to do? */
+             if (system(command_line)) ; /* TODO: what to do? */
 
              break;