Merge ~morphis/snappy-hwe-snaps/+git/network-manager:fix-startup-for-netplan-backend-switch into ~snappy-hwe-team/snappy-hwe-snaps/+git/network-manager:master

[Simon Fels]

Allow people to get ethernet managed back by NetworkManager

We now check on startup if network-manager should still managed ethernet or not and adjust our configuration depending on the existence of the 00-default-nm-renderer.yaml file in /etc/netplan

[Alfonso Sanchez-Beato (alfonsosanchezbeato)]

LGTM

review: Approve

diff --git a/bin/networkmanager b/bin/networkmanager
index 265bf7b..aa9db43 100755
--- a/bin/networkmanager
+++ b/bin/networkmanager
@@ -36,6 +36,12 @@ if [ ! -e "/etc/netplan/00-default-nm-renderer.yaml" ] ; then
         echo "unmanaged-devices+=interface-name:eth*,interface-name:enx*" >> $SNAP_DATA/conf.d/disable-ethernet.conf
     fi
 else
+    # Enable ethernet management again if the user switched the netplan
+    # backend and wants us to manage ethernet
+    if [ -e $SNAP_DATA/conf.d/disable-ethernet.conf ] ; then
+        rm -f $SNAP_DATA/conf.d/disable-ethernet.conf
+    fi
+
     if [ ! -e "$SNAP_DATA/conf.d/no-auto-default-ethernet.conf" ] ; then
         # If we're running as the only network management service
         # and are configured via netplan on first boot then we should