Add a default shell variable for the nic.

Dockerfile

@@ -179,7 +179,7 @@ RUN touch Launch.sh \
     && tee -a Launch.sh <<< '-drive id=MacHDD,if=none,file=${IMAGE_PATH:-/home/arch/OSX-KVM/mac_hdd_ng.img},format=qcow2 \' \
     && tee -a Launch.sh <<< '-device ide-hd,bus=sata.4,drive=MacHDD \' \
     && tee -a Launch.sh <<< '-netdev user,id=net0,hostfwd=tcp::${INTERNAL_SSH_PORT:-10022}-:22,hostfwd=tcp::${SCREEN_SHARE_PORT:-5900}-:5900, \' \
-    && tee -a Launch.sh <<< '-device ${NETWORKING},netdev=net0,id=net0,mac=${MAC_ADDRESS:-52:54:00:09:49:17} \' \
+    && tee -a Launch.sh <<< '-device ${NETWORKING:-e1000-82545em},netdev=net0,id=net0,mac=${MAC_ADDRESS:-52:54:00:09:49:17} \' \
     && tee -a Launch.sh <<< '-monitor stdio \' \
     && tee -a Launch.sh <<< '-vga vmware \' \
     && tee -a Launch.sh <<< '${EXTRA:-}'