SDL_QueryTexture and SDL_DestroyTexture require that the input texture
pointer be non-null. Debug builds of SDL will correctly check for this
and break program execution. This patch fixes this by checking the
status of the texture pointer.
Signed-off-by: Matt Oliver <protogonoi@gmail.com>
(cherry picked from commit 6be690685a8876a61f87b2b8bf30547e09030a96)