Xi: Fix segfault when removing slave
Kept running into a segfault somewhere in GetDeviceUse whenever I tried to remove a device. This happened on manual removal or on server shutdown. Now in XISendDeviceHierarchyEvent we don't try to read properties of recently removed devices.
segfault_when_removing_masters in 6 minutes and 21 seconds (queued for 2 seconds)4 jobs for