Move unity8's greeter off the "/" DBus path

[Michael Terry]

We expose the Greeter DBus API (whether we're active, which user is selected, etc) on the root / DBus path. This can easily conflict with other potential APIs (which are similarly rude as us to claim such a path).

We should switch away from it. Potential clients right now:

- indicators
- test tools
- adb
- telephony stack
- mtp stack
- push stack
- maliit
- messaging app (?)
- SDK (unlocks device when deploying apps)

While switching, it may be wise to move to some more standard APIs as well, like using logind's LockedHint instead of IsActive.

[Michał Sawicz (saviq)]

grep shows:

$ sudo grep -r UnityGreeter /usr
Binary file /usr/lib/arm-linux-gnueabihf/indicator-display/indicator-display-service matches
Binary file /usr/lib/arm-linux-gnueabihf/unity8/qml/IntegratedLightDM/libIntegratedLightDM-qml.so matches
Binary file /usr/lib/arm-linux-gnueabihf/qt5/qml/Ubuntu/Telephony/libtelephonyservice-qml.so matches
Binary file /usr/lib/arm-linux-gnueabihf/indicator-sound/indicator-sound-service matches
Binary file /usr/lib/ubuntu-push-client/ubuntu-push-client matches
Binary file /usr/lib/maliit/plugins/libubuntu-keyboard-plugin.so matches
Binary file /usr/bin/telephony-service-handler matches
Binary file /usr/bin/telephony-service-approver matches
Binary file /usr/bin/mtp-server matches
Binary file /usr/bin/telephony-service-indicator matches
/usr/share/upstart/sessions/mtp-server.conf: # Fix for bug LP: #1389223: UnityGreeter isn't available immediately
/usr/share/upstart/sessions/mtp-server.conf: --dest=com.canonical.UnityGreeter \

[Michał Sawicz (saviq)]

Some more:

/etc/apparmor.d/usr.bin.messaging-app: peer=(name=com.canonical.UnityGreeter,label=unconfined),
/home/phablet/.cache/upstart/mtp-server.log:E0705 15:56:03.168953 19890 server.cpp:443] Could not start the MTP server:org.freedesktop.DBus.Error.UnknownInterface: Interface com.canonical.UnityGreeter was not found in object /
/home/phablet/.cache/upstart/ubuntu-push-client.log:2016/07/05 14:59:38.113775 ERROR GetUnityGreeter call returned org.freedesktop.DBus.Error.UnknownInterface: Interface com.canonical.UnityGreeter was not found in object /
/home/phablet/.cache/upstart/indicator-display.log:(process:4867): indicator-display-WARNING **: Greeter: Error getting IsActive property: GDBus.Error:org.freedesktop.DBus.Error.UnknownInterface: Interface com.canonical.UnityGreeter was not found in object /

Wut?
Binary file /opt/click.ubuntu.com/com.ubuntu.terminal/0.7.198/lib/arm-linux-gnueabihf/com/ubuntu/PamAuthentication/libPamAuthentication.so matches
Binary file /opt/click.ubuntu.com/com.ubuntu.filemanager/0.4.543/lib/arm-linux-gnueabihf/com/ubuntu/PamAuthentication/libPamAuthentication.so matches
Binary file /opt/click.ubuntu.com/com.ubuntu.filemanager/0.4.543/lib/i386-linux-gnu/com/ubuntu/PamAuthentication/libPamAuthentication.so matches
Binary file /opt/click.ubuntu.com/com.ubuntu.filemanager/0.4.543/lib/x86_64-linux-gnu/com/ubuntu/PamAuthentication/libPamAuthentication.so matches
Binary file /opt/click.ubuntu.com/ut-tweak-tool.sverzegnassi/0.2.48/lib/arm-linux-gnueabihf/com/ubuntu/PamAuthentication/libPamAuthentication.so matches