Hello,

In my previous patch which introduced the AV_CUDA_USE_CURRENT_CONTEXT
feature I unintentionally made a mistake of not checking this flag when
uninitializing the CUDA.
It was causing cuda_device_uninit() function to destroy the CUDA context it
didn't create.

So far it only reproduces under cuda compute sanitizer:

========= COMPUTE-SANITIZER

========= Program hit invalid device context (error 201) on CUDA API call
to cuCtxDestroy_v2.


But nonetheless shall be fixed. Please find a fix in attached file, now
cuCtxDestroy is called under condition.