RFC - oleaut32: Cope with invalid icon data

[Bruno Jesus]

While testing bug [1] I noticed that invalid data is sent to
OLEPictureImpl_LoadIcon. This patch is meant to resist these kind of
issues and makes the game goes on a little further until other crash.

I'm sending this as RFC because I don't know then icon structure but
my tests seem very straight forward from what I can guess from the
function.

[1] https://bugs.winehq.org/show_bug.cgi?id=21012

Thanks in advance and best regards,
Bruno