Suspend laptop while ethernet is connected with wifi disabled, unplug ethernet, wake laptop, NetworkManager never recovers

[Jonathan Kamens]

Repro steps:

1. Configure ethernet not to enable automatically when plugged in.
2. Plug laptop into ethernet and enable ethernet connection.
3. Disable wifi.
4. Confirm that you have network connectivity.
5. Suspend laptop.
6. Unplug ethernet.
7. Wake laptop.

NetworkManager hangs forever trying to reestablish the ethernet connection that is no longer there. You can't even interrupt it because the "Disconnect" menu item is greyed out (see screenshot). Only recovery is to restart NetworkManager. Sometimes it seems like I even have to restart it twice to recover.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: network-manager 1.4.4-1ubuntu3
ProcVersionSignature: Ubuntu 4.10.0-21.23-generic 4.10.11
Uname: Linux 4.10.0-21-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
CurrentDesktop: Unity:Unity7
Date: Wed Jun 7 13:18:23 2017
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2017-05-19 (19 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
IpRoute:
 default via 192.168.43.1 dev wlp3s0 proto static metric 600
 169.254.0.0/16 dev virbr0 scope link metric 1000 linkdown
 192.168.43.0/24 dev wlp3s0 proto kernel scope link src 192.168.43.50 metric 600
 192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
mtime.conffile..etc.NetworkManager.NetworkManager.conf: 2017-05-19T14:16:03.840790
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.4.4 connected started full enabled enabled enabled enabled enabled