dix: Check for NULL spriteInfo in GetPairedDevice

There is a race when reseting the XServer that causes spriteInfo to be
NULL in GetPairedDevice resulting a segfault and subsequent crash. The
problem was noticed when opening a connection, creating master devices,
destroying master devices and closing the connection during testing.

Signed-off-by: Arthur Williams <taaparthur@gmail.com>


(cherry picked from commit e693c965)
3 jobs for cherry-pick-e693c965 in 6 minutes and 50 seconds
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debian-testing

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  Build And Test
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autotools-build-and-test

00:06:17

passed #1861603
meson-build-and-test

00:01:16