x264 would try to use the passed param struct after freeing if the param_free callback was set.
Probably didn't cause any issues, as probably no programs used the callback in this location yet.

A new x264_encoder_parameters function is now available in the API.
This function lets the calling application grab the current state of the encoder's parameters.
Use this in x264cli to ensure that the param struct used for set_param is updated with whatever changes x264_encoder_open has made to it.

Patch partially by Anton Mitrofanov <BugMaster@narod.ru>.