[wayland] Avoid compare to unintialised value in keyboard repeat
Summary:
If we get a key event for which
if (m_xkb->shouldKeyRepeat(key) &&
waylandServer()->seat()->keyRepeatDelay() != 0) fails
m_key will be unitialised and on release we have a compare against
unitialised memory.
Won't do any harm, it'll just stop a timer that isn't running, but
valgrind complains.
0 is the value QKeyEvent uses when nativeScanCode is unknown so a safe
initial values.
Reviewers: KWin, zzag
Reviewed By: KWin, zzag
Subscribers: kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D23748