Revert r20249, it seems the union trick works everywhere

Revert r20249, it seems the union trick works everywhere
Original commit message:
	Very evil missuse of svn to test if AVOption and AVOption2 are compatible.
	If this test triggers anywhere for anyone, revert this commit immedeatly.
	Ill revert this in a day or 2, its just so we know beforehand if the idea
	with the union is doable or not without breaking ABI/API.

Originally committed as revision 20264 to svn://svn.ffmpeg.org/ffmpeg/trunk