meta-google: google-usb-network: Cleanup gadget if setup fails

If setup fails for any reason, we want to cleanup any of the gadget
functions that were created.

Change-Id: I61be13a66cba2916fe7685b021fe0f7fa225e4f6
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/recipes-google/networking/google-usb-network/usb_network.sh b/meta-google/recipes-google/networking/google-usb-network/usb_network.sh
index 6f2c4d5..3c38fb4 100755
--- a/meta-google/recipes-google/networking/google-usb-network/usb_network.sh
+++ b/meta-google/recipes-google/networking/google-usb-network/usb_network.sh
@@ -185,5 +185,8 @@
 if [[ $ACTION == "stop" ]]; then
     gadget_stop
 else
-    gadget_start
+    rc=0
+    gadget_start || rc=$?
+    (( rc == 0 )) || gadget_stop || true
+    exit $rc
 fi