Initialize xv_need_bobdeint_repaint in ctor

Commit c2b16837b13d58700d0e1267d8ce36a6ff858fa3
added the xv_need_bobdeint_repaint member variable
but did not add it to the ctor.

Fixes Coverity 700920

Fixes #11673

Signed-off-by: Paul Harrison <pharrison@mythtv.org>