google-usb-network: Recipe cleanup

Just some minor changes to make it easier to extend.

Change-Id: Ib368da9173983aa02759b9e8bce1c34231cdf391
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/recipes-google/networking/google-usb-network_git.bb b/meta-google/recipes-google/networking/google-usb-network_git.bb
index 083cb2e..e1d768f 100644
--- a/meta-google/recipes-google/networking/google-usb-network_git.bb
+++ b/meta-google/recipes-google/networking/google-usb-network_git.bb
@@ -28,7 +28,7 @@
 SRC_URI += "file://usb_network.service.m4"
 SRC_URI += "file://usb_network.sh"
 
-do_compile() {
+do_compile:append() {
     test "X${BMC_USB_ECM_PRODUCT_ID}" != "X" || bberror "Please define BMC_USB_ECM_PRODUCT_ID"
     test "X${BMC_USB_ECM_PRODUCT_NAME}" != "X" || bberror "Please define BMC_USB_ECM_PRODUCT_NAME"
     test "X${BMC_USB_ECM_BIND_DEV}" != "X" || bberror "Please define BMC_USB_ECM_BIND_DEV"
@@ -42,13 +42,13 @@
         -DM_BMC_USB_IFACE="${BMC_USB_IFACE}" \
         -DM_BMC_USB_BIND_DEV="${BMC_USB_ECM_BIND_DEV}" \
         -DM_SCRIPT_INSTALL_DIR="${bindir}" \
-        ${WORKDIR}/usb_network.service.m4 > ${S}/usb_network.service
+        ${WORKDIR}/usb_network.service.m4 > ${WORKDIR}/usb_network.service
 }
 
-do_install() {
+do_install:append() {
   install -d ${D}/${bindir}
   install -m 0755 ${WORKDIR}/usb_network.sh ${D}/${bindir}
 
   install -d ${D}${systemd_system_unitdir}
-  install -m 0644 ${S}/usb_network.service ${D}${systemd_system_unitdir}
+  install -m 0644 ${WORKDIR}/usb_network.service ${D}${systemd_system_unitdir}
 }