segfault when using only some interfaces

[tbarbette]

When using only some interfaces (eg only dpdk1 when there is in fact dpdk0 and dpdk1 on the machine) leads to a segfault, at least with epwget.

GetOutputInterface will return the "name" index instead of the interface index, therefore this line segfault :
api.c:936 saddr_base = g_config.mos->netdev_table->ent[nif_out]->ip_addr;
as nif_out should be 0 and not 1

[a-jamshed]

Thanks for reporting the bug. We will patch up the code to fix this issue soon.