WinRT: fixed bug whereby offscreen-rendered content could get improperly rotated

Attributes on the host device's rotation were getting applied to offscreen
textures in an invalid manner.  This was causing some apps to look different,
depending on how the device was rotated.

--HG--
extra : rebase_source : 6c4e6b4b6386c34677532d2744d4e351ae6e9be0