sdl2: fix mouse grab

When qemu mouse mode changes from relative to absolute
we must turn off sdl relative mouse mode too.

Fixes: https://bugs.launchpad.net/qemu/+bug/1703795
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20180202120803.11501-1-kraxel@redhat.com>
1 file changed